生平

征撫遼東－前燕文明帝慕容皝時期

慕容恪年幼時就已謹慎篤厚，深沈有大度，但因為母親高氏並不得寵，所以沒有被慕容皝所重視。直至慕容恪十五歲時，慕容皝才發覺他的才能，讓他掌兵。多次隨軍出征，都多有奇策。

東晉成帝(東晉)|咸康四年（338年）

後趙天王石虎率步騎十萬，水師十萬與其父前燕遼東公慕容皝一起進攻遼西段部鮮卑首領段遼，形成夾擊之勢，隨後攻下遼西之地。但而後石虎以慕容皝不前來會師為理由，率軍討伐慕容皝，數十萬大軍前來圍攻前燕都城棘城，沿途郡縣響應石虎而叛變的便有三十六座城池之多，慕容皝見後趙大軍兵勢極盛，本想出逃，但在部將慕輿根、玄菟太守劉佩的勸說力戰下堅定了對抗石虎的決心。

後趙軍隊在前燕將士的抵抗下，圍攻十餘日卻遲遲無法攻陷棘城，因此只好退兵。趁此時機，慕容皝派遣慕容恪率騎兵兩千人在凌晨殺出棘城，大敗後趙軍隊，斬首敵軍三萬多級。

咸康七年（341年）

經過慕容皝特使劉翔的努力下，東晉朝廷冊封其父慕容皝為使持節、大將軍、都督河北諸軍事、幽州牧、大單于、燕王並加殊禮。而後在冬十月，慕容恪被受命為度遼將軍，出鎮平郭（今遼寧蓋州市）。慕容恪安撫懷柔當地民眾，屢敗高句麗軍，令高句麗畏懼而不敢進犯前燕國境，繼慕容翰和慕容仁後成功安定遼東。

東晉晉康帝|康帝(東晉)|建元元年（343年）

春二月，高句麗王高釗因前一年前燕的攻伐而元氣大傷，遣使向前燕稱臣。燕王慕容皝便歸還其父乙弗利的屍體，將高釗的母親留下作為人質。。

建元二年（344年）

燕王慕容皝領兵親征宇文鮮卑頭領宇文逸豆歸，其中以慕容翰為前鋒將軍，劉佩為副手，而後分別命令慕容軍、慕容恪、慕容霸及折衝將軍慕輿根領兵，以三路並進的方式直逼宇文部。在慕容霸、等人的勇武下成功消滅宇文部，前燕領土闢地千餘里。

東晉晉穆帝|穆帝(東晉)|永和元年（345年）

冬十月，慕容恪再奉命進攻高句麗，攻陷南蘇城（今遼寧丹東五龍山南）並留兵戍守。。

永和二年（346年）

世子慕容儁與慕容恪和慕輿根率騎兵一萬七千人進攻夫餘國，此役慕容儁居中指揮，而慕容恪則率軍親身殺敵，所向披靡，終俘獲夫餘玄王以及其部落共五萬多人。而後慕容皝以餘玄為鎮軍將軍，還把女兒嫁給他為妻。

征戰中原－前燕景昭帝慕容儁時期

永和四年（348年）

慕容皝去世，臨死前囑咐慕容儁要重用慕容恪。慕容儁即位後，亦對慕容恪頗見親待。

永和五年（349年）

後趙皇帝石虎去世，國內因諸子爭位而大亂，慕容儁決心乘時奪取中原，於是以慕容恪為輔國將軍，與輔義將軍陽騖及輔弼將軍慕容評合稱「三輔」，慕容霸為前鋒都督、建鋒將軍。更選精兵二十多萬，作好出兵的準備。

永和六年（350年）

慕容儁分三路大軍南進，慕容恪任慕容儁所率軍隊的前鋒，成功攻下薊城（今北京）、范陽（今保定和北京一帶）等城池。隨後慕容儁安排幽州各地攻下的郡縣太守。

九月，慕容儁大軍直逼冀州，攻下章武、河間、樂陵等郡，並以慕容評為章武太守，封裕（封衡之父）為河間太守，受慕容恪和慕容儁器重，可以百步不傷牛隻射中毛髮的賈堅為樂陵太守，治高城。

永和七年（350年）

慕容恪又攻中山，遭冉魏中山太守侯龕及守將白同固守所阻，於是留兵繼續攻城，自己先攻常山。因慕容恪厚待投降的魏郡太守李邽，並與其一同回攻中山，令侯龕主動出降，慕容恪成功攻下中山，斬白同，並遷城內將帥、土豪數十家到薊城，其餘百姓的生活則一如往常，慕容恪軍令嚴明，對於百姓秋毫不犯。

永和八年（352年）

冉魏皇帝冉閔攻下襄國（今河北邢台），滅後趙，於是據掠前燕奪取的常山、中山各郡，慕容儁於是命慕容恪攻伐冉魏。慕容恪追冉閔軍，直至廉臺（今河北無極東）才追上。慕容恪屢次不能戰勝冉閔，因冉閔向來有勇猛的名聲，且手下都是精兵，所以令燕軍都忌憚他。慕容恪此時以冉閔有勇無謀、士卒飢疲來激勵軍心，亦聽從參軍高開建議引冉閔到有利於燕軍騎兵作戰的平地才決戰。成功引冉閔到平地後，慕容恪分兵三路，決心引冉魏全力進擊以鐵鎖連馬構成的中軍方陣，從而在側翼襲擊冉閔。最終冉閔兵敗被俘，後又擊殺前來襲擊的冉魏將領金光，進據常山。因著同時叛變的段勤投降，慕容儁命慕容恪回鎮中山，自己則率軍進攻冉魏都城鄴城，最終成功攻滅冉魏，入主中原。

八月戊辰，慕容恪受燕王慕容儁的命令與封弈、陽騖攻打自稱「安國王」的王午，王午見燕軍前來緊閉城門固守，把冉閔之子冉操送給前燕，燕人把他們的莊稼砍掠一空後返回。而後慕容恪屯兵安平，廣積糧食、製作攻城器具等，隋後先後擊敗王午、呂護、李犢、蘇林等反抗前燕的力量。

十一月戊辰，慕容儁稱帝，國號「燕」，年號「元璽」，史稱「前燕」。慕容恪獲授侍中、衞將軍。

永和九年（353年）

時任侍中、衞將軍的慕容恪與撫軍將軍慕容軍、左將軍慕容彪等人屢次推薦時任給事黃門侍郎的慕容霸，說他具有改變當世的優異才能，應該對其付以重任。因此，景昭帝便任命慕容霸為使持節、安東將軍、北冀州剌史，坐鎮常山。

永和十年（354年）

夏四月，景昭帝開始封賞諸位宗室大臣，為眾人加官進爵。其中慕容恪升任大司馬、侍中、大都督、錄尚書事，封太原王。已位極人臣。

永和十一年（355年）

冬十月，東晉鎮北將軍、齊公段龕因非議慕容儁叛晉稱帝一事激怒慕容儁。十一月，景昭帝於是任命太原王慕容恪為大都督、撫軍將軍，以陽騖為副手，率軍攻打段龕。景昭帝對慕容恪說道:「段龕軍隊強大，若他派兵拒守黃河河畔，無法渡河，那就轉向直取呂護。」於是慕容恪便派輕軍到黃河上觀察廣固城中段龕的意圖。段龕之弟段羆，驍勇善戰又有智謀。段羆對段龕進言：「慕容恪善於用兵，現在他兵力眾多，若任他渡過黃河，進軍城下，那時我們想投降，也不被允許了。請兄長固守城池，讓我率精兵到黃河抵禦，若戰勝，兄長率大軍跟進，定會成功。若戰敗，不如早點投降，還可保住千戶侯之位。」段龕不聽。段羆還是堅持，把段龕激怒，殺掉了段羆。

永和十二年（356年）

春正月，慕容恪渡過黃河，並於淄水大敗前來迎擊的三萬段龕軍，斬殺了段龕的右長史袁范，並抓住段龕之弟段欽，並進圍段龕固守的廣固（今山東青州市西北）。面對段龕堅守不出，慕容恪並未猛烈攻城，反而招降了段龕領下的王騰、薛雲等。及後段龕糧盡出城決戰，被圍城的慕容恪擊敗而狼狽撤回城中，被逼投降。後慕容恪又率兵成功抵禦東晉泰山太守諸葛攸的攻擊，進略河南等地。

東晉晉穆帝|穆帝昇平三年（359年）

十二月辛酉景昭帝慕容儁患病，對時任大司馬的太原王慕容恪說：「我病得這麼虛弱，恐怕是好不了。壽命長短，都沒有甚麼可怨恨的了！不過現在東晉和前秦未除，景茂（慕容暐字）年幼，擔心他應付不來。我想效法宋宣公，將皇位交給你，如何?」但慕容恪堅決拒絕的回道:「太子雖然年幼，但卻是可以使惡人從良、讓國家清平昌盛的明主，臣是何人，豈能幹預正統?」，慕容儁怒道:「兄弟之間，就不要講究虛偽的禮節了。」慕容恪再次回拒道：「陛下如果認為臣具有能夠承擔安定天下重責的才能，又為何認為臣就不能好好輔助少主！」慕容儁聽後欣慰的開心說道:「你能做周公，我就沒什麼好憂慮的了。」並推薦李績給慕容恪。後來慕容恪亦嚮慕容暐推薦李績，但慕容暐因舊怨而不肯重用他。

攝政安國－前燕幽帝慕容暐時期

昇平四年（360年）

春正月，慕容儁在鄴城舉行盛大的閱兵，想派大司馬慕容恪和司空陽騖領兵征討東晉，病情卻急轉直下，隨後不久去世，年僅11歲的太子慕容暐繼位，改元「建熙」，是為前燕幽帝。慕容儁臨終時遺命慕容恪與上庸王司徒慕容評、司空陽騖及領軍將軍慕輿根一同輔政。

二月，慕容恪於是升位太宰、錄尚書事，行周公事，總攝朝政。不過，當時作為太師輔政的慕輿根自恃戰功顯赫，顯得高傲自大，看不起慕容恪。慕輿根為挑起事端以作亂，先以可足渾太后幹政來挑撥慕容恪，說道:「今主上年幼，太后幹政，殿下應預防意外的發生，以保全自身，況且如今大燕江山，多出自殿下之手，兄終弟及乃是自古有之，故殿下應廢除主上，自立為帝才是，如此，才是我大燕的福氣啊。」，支持慕容恪奪位。但慕容恪不受，說道：「公喝醉了?怎敢說出如此大逆不道的言論，我等皆受先帝的託孤重任，怎可有此想法呢?」，慕輿根只好慚愧離去。吳王慕容垂以及皇甫真等人都勸他誅殺慕輿根，但慕容恪以皇帝新死，國家安穩為首要，決定忍耐。

慕輿根挑撥慕容恪不成，於是試圖離間慕容暐母子和慕容恪，想要太后誅殺慕容恪等，但慕容暐卻支持慕容恪，勸止了母親。與此同時，由於前燕已經在滅冉魏後遷都鄴城，留舊都龍城（今遼寧朝陽市）為留京，而慕輿根卻思戀遼東祖地，對太后和慕容暐建議還都龍城，變相放棄中原。慕容恪知道後就與慕容評密奏慕輿根罪狀，最終誅殺了慕輿根及其黨羽。

面對皇帝新死，更發生了誅殺重臣的事件，國內都憂慮情緒都很高，但慕容恪卻顯得舉止如常，出入都只有一人跟從，不肯加添守衞，於是令人心稍為安定。同時，原先徵集在鄴城的各郡軍人都因為國家內部紛亂而經常逃跑，而鄴城向南方領地的道路通訊仍不通，故慕容恪又命慕容垂為使持節、征南將軍、都督河南諸軍事、兗州牧、荊州刺史，鎮守蠡臺（今河南商丘），傅顏為護軍將軍，率領騎兵二萬人南巡至淮河，終令國家安穩下來。

十一月，身為太宰的慕容恪想要任命李績為尚書右僕射，幽帝慕容暐卻因昔日曾經被李績向其父說道喜好遊獵音樂的舊怨，因而不允許。慕容恪屢次請求皆不被答應，而後慕容暐說道：「國家一切事務，皆委託叔父，但伯陽(李績的字)這個人，就交給我處理裁斷吧」於是李績被任命為章武太守，最後在任上鬱鬱寡歡，不得志而死。

力奪洛陽

昇平五年（361年）

據守野王，原本已歸附前燕的河內太守呂護叛歸東晉，被任命為冀州刺史。而後呂護想引東晉軍隊前來攻打前燕都城鄴城。

於是在三月，太宰慕容恪率兵5萬與冠軍將軍皇甫真率兵1萬前去討伐呂護。大軍到了野王後，呂護環城防守，護軍將軍傅顏請求快速將其攻陷，以減少損耗，但慕容恪決定以逸待勞，起長圍作持久戰。

最終在圍城數個月以後，成功逼得糧盡的呂護出擊並大敗對方，令其元氣大傷，被逼出逃滎陽。慕容恪又招撫其餘眾。而後呂護再次背叛東晉，投奔前燕，前燕朝廷赦免其罪，任命他為廣州刺史。及後慕容恪又派兵攻略許昌、汝南、陳郡等地，並派遣鎮南將軍慕容塵屯兵許昌。東晉駐洛陽的守軍漸見孤立，援兵和糧食都缺乏。

東晉晉哀帝|哀帝(東晉)|興寧二年（364年）

前燕太宰慕容恪為了攻占洛陽而做了多方準備，派遣手下去招納當地的士民，於是遠近諸塢都歸降前燕。之後便派遣他手下的司馬悅希屯兵於盟津（今河南省孟津縣東北，古代黃河渡口名），豫州刺史孫興屯兵於成皋，以備之後的洛陽征討。

興寧三年（365年）

二月，太宰慕容恪與吳王慕容垂一同進攻洛陽，慕容恪對諸將說道：「眾位常憂慮我不攻，如今洛陽城高而兵力疲弱，極易攻克，切勿畏懦而因此怠惰！」隨後便下令攻打，當時洛陽守將東晉冠軍將軍陳祐已棄守洛陽，只餘下揚武將軍沈勁所率五百人守城。

三月，最終成功攻下洛陽，並俘虜了沈勁，慕容恪本想赦免他，但中軍將軍慕輿虔認為，沈勁乃是當世奇士，且不會為前燕所用，放他走必成後患，只好殺了沈勁。

而後慕容恪帶兵一路攻陷崤山、澠池等地，使得關中大為震動，連前秦天王苻堅趕緊率兵屯於陝城（今河南三門峽市以西）以防慕容恪來攻。

而後前燕任命左中郎將慕容築為洛州刺史，鎮守在金墉，吳王慕容垂為都督荊、揚、洛、徐、兗、豫、雍、益、涼、秦十州諸軍事、征南大將軍、荊州牧，領兵一萬，鎮守在魯陽。慕容恪回到鄴城以後，對於殺掉沈勁，覺得十分愧疚。

遺薦吳王

東晉晉廢帝|廢帝(東晉)|太和元年（366年）

三月，前燕太宰、大司馬慕容恪與太傅、司徒慕容評，決心歸政於已經17歲的幽帝慕容暐，將官印及權力交出去，但卻被慕容暐拒絕。

太和二年（367年）

慕容恪很早就知道慕容垂的才能，並曾嚮慕容儁推薦。不過慕容儁始終猜忌慕容垂，一直都不放心任用。

五月，慕容恪患病甚是嚴重，臨死前慕容暐來詢問後事，慕容恪於是嚮慕容暐推薦吳王慕容垂接替自己。他又知道慕容暐政不在己，慕容評常猜忌他人，於是也嚮慕容臧及慕容評推薦慕容垂為大司馬。

不過，慕容評最終都沒有聽從慕容恪的話，反倒更逼慕容垂出走前秦，終招來前秦滅國。慕容恪死後，前燕舉國痛惜，而桓溫和苻堅知道慕容恪死訊後亦開始準備攻伐前燕。慕容恪獲賜諡號桓。

性格特徵

• 慕容恪高八尺七寸，嚴肅穩重。

• 慕容恪雖綜大政，但每事必與叔父慕容評商議，未嘗獨斷。同時亦虛心對待士人，善於諮詢他人意見，因應官員的才能而授官。而官員若有過失，慕容恪都不會當眾揭破，也不會貶他們的官，只是調他們到別的位置，就作為對他們的貶謫。當時的人因為慚愧，都不敢犯罪，犯了小過亦會自責。另慕容恪亦擅長軍事，守遼東、伐高句麗、征扶餘、取中原、平段龕等各項戰事都展現出其軍事才能。桓溫在慕容儁死後仍覺得未是時機攻伐前燕，就是因為顧慮慕容恪的才能，他不僅是戰場上的強將，亦是能匡扶前燕的能臣。

• 慕容恪為國盡忠，如曾有一個叫丁進的方士，很得慕容暐寵信，更圖討好慕容恪，勸他殺死太傅慕容評。而慕容恪沒有動容，亦不以他得皇帝寵信而顧忌，即上奏將其處斬。

• 慕容恪帶兵不以身份欺凌部屬，而是加以恩惠與信任，在軍務上則是把握大原則，不會太嚴苛，使士卒可以安心待在軍營。平時營中雖然寬縱，對手看來好像有機可乘，然而警備嚴密，敵人來到卻無法靠近，因此慕容恪打仗未嘗吃過敗仗。

評論

• 慕容皝：「今中原未一，方建大事，恪智勇俱濟，汝其委之。」

• 段羆：「慕容恪善用兵。」

• 王猛：「慕容玄恭信奇士也，可謂古之遺愛矣！」

• 崔浩：「慕容恪之輔幼主，慕容暐之霍光也。」

• 成海應:「玄恭之材之性, 似非夷裔之產也. 蓋慕容氏, 部族英傑之多, 最於五胡, 而玄恭為最. 非但行師攻敵, 皆合機宜, 其憂國忠勤, 如孔明之於蜀也, 羊祐之於荊也. 使玄恭不死, 暐雖庸主, 獨不可保燕乎. 殆鮮卑之運將竭, 玄恭安得久生乎. 秦雖強盛, 且王猛柄國, 在玄恭時, 無所著見矣.」

• 明·張大齡:「慕容自龍驤以來，世豪東夏，其子孫俱英朗雄傑，發在童孺，天之所興，其誰廢之！太原德業邁於狐趙，吳王才器不下管蕭。昔舜生諸馮，東夷之人可以其鮮卑而少之？償恪而不死，更得明主事之，與吳王垂左提右挈，驅駕才俊，混一之業，指顧而定矣！乃吳王力足以討評，而不為首亂；時足以取堅，而還其舊兵；威足以困丕，而開以生路，尤人所難者。至於八十之齡，取西燕如拾芥，挫魏兵如發蒙，真太原所謂命世之才也。後來亡國之主，猶自翹然，身在鼎俎，神色不變。蓋先世大有功德，故子孫蹶而復奮，不若諸胡之一敗塗地。予於和龍之君，獨有取爾者以此。太尉裕平燕之日，欲坑廣固，得韓範諫而止。嗚呼！燕何罪哉！前燕開基，取之劉石。後燕恢復，奪之苻秦。燕何罪哉！而戮之若斯之慘也。太尉此舉，不惟遠愧三代吊伐之師，且近有怍於玄恭景略矣。惜哉！」

• 明·王夫之:「五胡旋起旋滅，而中原之死於兵刃者不可殫計。殫中原之民於兵刃，而其旋起者亦必旋滅。其能有人之心而因以自全者，唯慕容恪乎！故中國之君，一姓不再興，而慕容氏既滅而復起。恪圍段龕於廣固，諸將請亟攻之，恪曰：「龕兵尚眾，未有離心，盡銳攻之，殺吾士卒必多矣，自有事中原，兵不暫息，吾每念之，夜而忘寐，要在取之，不必求功之速。」嗚呼！惻悱之言，自其中發，功成而人免於死，恪可不謂夷中之錚錚者乎！」

地位

唐宋武成王廟位列其中。

家庭

母

高氏，慕容皝的妾室，高氏不得寵，所以慕容恪年幼時沒有被慕容皝所重視。

子媳

• 慕容楷，太原王，諡元。

• 慕容楷妻、蘭汗女蘭氏

• 慕容肅，384年與慕容暐一同被苻堅所殺

• 慕容紹，陳留王，395年卒于參合陂之戰，諡悼，

孫輩

• 慕容楷與蘭汗女蘭氏之子慕容奇

後裔

出自北史、北齊書、隋書、《隋故金紫光祿大夫淮南郡太守河內公慕容府君墓誌銘並序》、《大周故左肅政臺侍御史慕容府君墓誌》、《大周故相州臨漳縣令慕容府君墓誌》、《唐故太中大夫隰州司馬慕容府君墓誌》、《大唐故洺州肥鄉縣尉慕容府君墓誌》、《唐故三品孫慕容君（知禮）墓誌銘並序》 、《大唐故朝散大夫上柱國行河內郡武德縣令慕容府君（相）兼夫人晉昌縣君唐氏誌文並序》、《大周故左衛翊衛天官常選慕容府君（思觀）墓誌銘並序》、《唐故河南府澠池縣丞慕容君（瑾）墓誌銘並序》

• 三代孫（曾孫）：慕容騰，歸降北魏後，居住在代郡（今河北蔚縣一帶），子慕容鬱

• 四代孫：慕容鬱，北魏昌黎郡公、岐州刺史，子慕容遠

• 五代孫：慕容遠，北魏昌黎郡公、并州大中正、恆州刺史，子慕容紹宗

• 六代孫：慕容紹宗（501年－549年），東魏燕郡景惠公、永樂縣子，官至東魏尚書左僕射、東南道大行台，節度三徐、二兗州軍事、開府儀同三司，追贈武威郡王。子慕容士肅、慕容三藏

• 七代孫：

　• 慕容士肅：東魏散騎常侍，而後以謀反伏誅

　• 慕容三藏（546年－613年7月3日）：先為北齊燕郡公、開府儀同三司、右衛將軍、加封范陽縣公，後為北周開府儀同大將軍、吳州刺史，再後來為隋朝河內縣開國公、金紫光祿大夫、淮南郡太守，有子慕容正言、慕容正則

• 八代孫：

　• 慕容正言：唐朝請大夫（從五品上）、行衛州長史（上州，從五品上）、兗州都督府司馬（上都督府，從四品下），有子慕容知廉、慕容知敬、慕容知禮、慕容知晦

　• 慕容正則：隋工部侍郎（正四品）、後來唐時為隴州吳山縣令（中縣，正七品上），有子慕容懷固、慕容思廉、慕容思觀

• 九代孫：

　• 慕容知廉（640年－698年）：武周左肅政臺侍御史（從六品下），有子慕容相

　• 慕容知敬：唐絳州司戶參軍事（雄州，從七品下），有子慕容昇

　• 慕容知禮（641年－659年）：

　• 慕容知晦：唐汾州刺史（望州，從三品），有子慕容瑾

　• 慕容思觀（?年－684年）：武周左衛翊衛天官常選

　• 慕容思廉（630年－712年）：唐太中大夫（從四品上）、隰州司馬（下州，從六品上）

　• 慕容懷固（?－702年）：武周相州臨漳縣令（上縣，從六品上）

• 十代孫：

　• 慕容相（677年－731年）：知廉第四子，唐朝散大夫（從五品下）、上柱國（視同正二品）、行河內郡武德縣令（望縣，從六品上）

　• 慕容昇：唐洺州肥鄉縣尉（上縣，從九品上）

　• 慕容瑾：唐河南府澠池縣丞（畿縣，正八品下）

注釋

Early life

Murong Ke was Murong Huang's fourth son, by his concubine Consort Gao. In the Book of Jin, Murong Ke was described as over 2.1 metres tall and had an imposing look when he was just 15 years old. In his youth, he became known for his deep-thinking and tolerance of others, but was not viewed highly by his father because his father did not favor his mother. Only after he turned 14, when his father began to be impressed by the strategies that he had, was he given important responsibilities. Sometime before 345, he was given the important defense post of Liaodong (遼東, in modern Liaoyang, Liaoning) with the responsibility of defending the eastern border against Goguryeo. In 345, he was sent by Murong Huang to launch an attack on Goguryeo, and the attack was successful. In 346, formally under the command of his brother, the heir apparent Murong Jun, but with him in actual command, he attacked Buyeo (Fuyu (夫餘) in Chinese), capturing its capital and its king Fuyu Xuan (夫餘玄).

In 348, Murong Huang neared death, and he told Murong Jun that he should rely on his brother Murong Ke if he wanted to accomplish great things. He died soon thereafter and was succeeded by Murong Jun, who made Murong Ke one of his major generals.

During Murong Juns reign

In 349, as rival Later Zhao was collapsing in light of internecine wars between the sons of the deceased emperor Shi Hu and his adoptive grandson Shi Min, Murong Jun, under the advice of another brother Murong Ba, planned an invasion into the North China Plain, and Murong Ke was one of the major generals for the planned invasion. In 350, Former Yan forces quickly captured Later Zhao's You Province (幽州, modern Beijing, Tianjin, and northern Hebei). Murong Ke's military discipline was said to be so strict that not even trees and grass were harmed as his army marched through a region, and he quickly seized a number of commanderies in Ji Province (冀州, modern central Hebei) from Ran Wei, the new state established by Shi Min (who had by now changed his name to Ran Min, back to the family name that his father had before he was adopted by Shi Hu).

In 352, Ran Min marched north, ready to engage Former Yan forces. Former Yan soldiers were apprehensive of Ran Min's reputation for being a fierce warrior, but Murong Ke devised a plan to trap Ran, whose forces were largely infantry and had been based in forests. Murong Ke pretended to repeatedly lose engagements, and Ran Wei forces were drawn into the plains. Murong Ke then put his cavalry into square formations, with horses locked in formations with chains, and the Ran Wei infantry could not stand the pressure and collapsed. Ran Min was still battling when his horse suddenly died, and he fell and was captured. Murong Jun executed him and then marched on to the Ran Wei capital Yecheng (鄴城), where Ran Min's wife Empress Dong, his crown prince Ran Zhi, and high level officials continued to try to fend off Former Yan for a while, but late in 352, Yecheng fell, and most of Ran Wei's territory fell to Former Yan. When Murong Jun then claimed imperial title, he created Murong Ke the Prince of Taiyuan in 353.

During the next few years, as a number of former Later Zhao generals were still trying to maintain independence and vacillated between Former Yan, Former Qin, and Jin, Murong Ke was involved in a number of successful campaigns to destroy them or force their submission. These included campaigns against Su Lin (蘇林) in winter 352, Li Du (李犢) in summer 353, and Lü Hu (呂護) in spring 354. In 356, Murong Ke further defeated Duan Kan (段龕), the Jin vassal who had occupied Shandong Peninsula under the title Duke of Qi, sieging his heavily fortified capital Guanggu (廣固, in modern Qingzhou, Shandong) and forcing his surrender. In 358, he repelled a Jin attack led by Zhuge You (諸葛攸) and further counterattacked, seizing a number of Jin commanderies south of the Yellow River.

Around new year 360, Murong Jun grew ill, and he told Murong Ke that since his 10-year-old son, Murong Wei the Crown Prince, was too young, and that the empire was facing threats from Jin and Former Qin, he was ready to pass the throne to Murong Ke. Murong Ke declined, persuading Murong Jun that if his abilities were capable of ruling over the empire, then they were also capable of assisting the young emperor. Murong Jun soon died, entrusting his son to Murong Ke, Yang Wu, his uncle Murong Ping the Prince of Shangyong, and Muyu Gen, but with Murong Ke as regent.

As regent for Murong Wei

Murong Ke soon had to face a challenge against Muyu Gen, who considered himself the senior official, having accomplished much during the reigns of Murong Huang and Murong Jun, and was unwilling to submit to the much younger Murong Ke. He first tried to create a rift by trying to persuade Murong Ke to take over the throne—which Murong Ke rebuked him about but declined to kill him despite suggestions to do so from Murong Chui (formerly known as Murong Ba) the Prince of Wu and Huangfu Zhen. Instead, Muyu then tried to persuade Murong Jun's wife Empress Dowager Kezuhun and the young emperor that Murong Ke and Murong Ping were planning a rebellion. Empress Dowager Kezuhun believed him, but the emperor did not and refused to authorize action. After Murong Ke heard about this, he executed Muyu and his coconspirators. With Murong Jun recently deceased and a major purge having followed, the officials in the Former Yan regime all were terrified, but Murong Ke calmed them by calm demeanor—including only having one servant accompany him wherever he went, without heavy guards. As far as his military command style was concerned, this was said about it in Sima Guang's Zizhi Tongjian:

:Murong Ke did not rely on terrorizing his army with punishments, but relied on kindness and faithfulness. He calmed his soldiers and paid attention to important things, and did not micromanage. Everyone felt protected by order. In ordinary times, the military laws were relaxed, and it might appear as if he lacked discipline and could be defeated easily. Instead, reality was that he paid great care to defense, and enemies could not get close. Therefore, he never lost a battle.

Indeed, in recorded history there was not a single mention that Murong Ke lost a battle. He was also described as a capable regent, being humble and willing to listen to suggestions. He did not deal out heavy punishments for officials' mistakes, and he consulted with Murong Ping on all important decisions. In 361, a magician much favored by the young emperor, Ding Jin (丁進), tried to flatter Murong Ke by persuading him to kill Murong Ping and take all power. Murong Ke, instead, had the magician executed. Later that year, Lü Hu, whom Murong Ke had forced the surrender of years earlier, rebelled, and Murong Ke defeated him, forcing him to flee to Jin.

In 364, Murong Ke led an army against Luoyang, which had been in Jin hands since 356. In 365, after a fierce attack, Luoyang fell, and he captured the Jin general Shen Jing (沈勁), whom he initially wanted to spare, but who continuously refused to submit and therefore whom his deputy Muyu Qian (慕輿虔) insisted on executing. Murong Ke, upon return to Yecheng, stated that he felt ashamed that he was unable to preserve Shen's life and allow his abilities to be used by Former Yan.

In 366, both he and Murong Ping offered to resign their posts and return all authority to the 16-year-old emperor Murong Wei. Murong Wei declined.

In 367, Murong Ke grew ill. He was afraid that a post that was part of his responsibility, the commander of the armies, would be given in an inappropriate person. He therefore tried to persuade Murong Wei's older brother Murong Zang (慕容臧) the Prince of Le'an and Murong Ping that the post should be given to Murong Chui, whose abilities he was greatly impressed with (but who had been viewed with suspicion by Empress Dowager Kezuhun). On his death bed, he also tried to persuade the young emperor of the same thing. However, after he died later that year, Murong Ping disagreed and took most of the power, giving the commander of the armies post to Murong Wei's younger brother Murong Chong the Prince of Zhongshan. What Murong Ke feared happened, as with Murong Ping in charge, Former Qin destroyed Former Yan in 370, just three years after his death. (As Former Qin's capable prime minister Wang Meng approached the Former Yan capital Yecheng, his army showed the same discipline that Murong Ke's did, and the people joyously stated, "We have met the Prince of Taiyuan again!" Upon hearing this, Wang, who had been quite confident about his own abilities, became impressed at Murong Ke, and sent messengers to offer sacrifices to him.)

Descendants

The Eastern Wei general, Murong Shaozong (慕容绍宗), was also his descendant.

Sons

• Murong Kai (慕容楷), Prince of Taiyuan (created 384).

• Murong Su (慕容肅), executed by Fú Jiān 384 along with Murong Wei

• Murong Shao (慕容绍), Prince of Chenliu, killed in Battle of Canhe Slope 395

Grandsons

• Murong Qi (慕容奇), son of Murong Kai and a daughter of Lan Han, would succeed Kai's title and died 395.