Early career

Sima Ying was Emperor Wu of Jin's 16th son, by his concubine Consort Cheng. In 289, Emperor Wu created him the Prince of Chengdu. After Emperor Wu died in 290 and Emperor Hui succeeded to the throne, Sima Ying remained in the capital Luoyang. However, after he once rebuked Jia Mi (賈謐), the nephew of Emperor Hui's powerful wife Empress Jia Nanfeng, for disrespecting Emperor Hui's son Sima Yu the crown prince, Empress Jia sent Sima Ying away from the capital to take up the defense post for the important city of Yecheng (鄴城, in modern Handan, Hebei). Sima Ying was handsome but not much more intelligent than his developmentally disabled brother Emperor Hui, but he developed a good reputation among officials and the people by being lenient, filial to his mother Princess Dowager Cheng, and listening to the advice of his capable advisor Lu Zhi (盧志).

After Empress Jia falsely accused Crown Prince Yu of crimes and deposed in 299 and then further murdered him in 300, she was overthrown by Emperor Hui's granduncle Sima Lun the Prince of Zhao. Sima Lun then usurped the throne in 301. Suspecting three key princes—Sima Ying, Sima Jiong the Prince of Qi (Emperor Hui's cousin and the son of Emperor Hui's uncle, Prince You of Qi), and Sima Yong the Prince of Hejian (the grandson of Emperor Hui's great-granduncle Sima Fu the Prince of Anping), each of whom had strong independent military commands—Sun sent his trusted subordinates to be their assistants. Prince Jiong refused and declared a rebellion to restore Emperor Hui. At Lu's suggestion, Sima Ying declared for the rebellion as well, and as Sima Jiong's forces were stuck in a stalemate against Sima Lun's troops, Sima Ying defeated the other wing of Sima Lun's forces, causing them to collapse. As Sima Jiong and Sima Ying's forces approached Luoyang. Sima Lun was captured by officials in Luoyang who declared for the rebellion as well, and forced to issue an edict returning the throne to Emperor Hui. He was then forced to commit suicide. The associates of Sima Lun were executed.

After overthrowing Sima Lun

Some thought that a power balance that Emperor Wu had hoped for at his death might be restored, as Princes Jiong and Ying were each given regent titles (and awarded the nine bestowments, in one rare case where the nine bestowments were not signs of an impending usurpation, although Prince Ying declined the bestowments), and many talented officials were promoted into important positions. However, the Princes Jiong and Ying were actually apprehensive of each other's power, and Prince Ying decided to yield the central government regency to Prince Jiong at the time and return to his defense post at Yecheng. When he bid farewell to Sima Jiong, he did not talk about politics at all but only about his mother's illness, and this brought further praise on his character, as did his subsequent acts to collect the bodies of soldiers who had died in the war against Sima Lun to give them proper burials.

In the capital, Sima Jiong became arrogant based on his accomplishments. He had his sons created princes, and ran the matters of the central government from his mansion, rarely visiting the emperor or attending the imperial meetings. He enlarged his mansion to be as large as the palace, and he entrusted matters to people who were close to him, and would not change his ways even when some of his more honest associates tried to change his behavior. When Emperor Hui's grandsons Sima Zang and Sima Shang, successive crown princes, died in childhood, leaving Emperor Hui without male descendants by 302, Sima Ying was considered the appropriate successor, but Sima Jiong chose to bypass him by recommending the seven-year-old Sima Qin the Prince of Qinghe (Emperor Hui's nephew and the son of his brother Sima Xia) as the crown prince, with intent to easily control the young Crown Prince Qin.

Sima Jiong became suspicious of Sima Yong the Prince of Hejian—because Sima Yong had initially wanted to support Sima Lun, until he saw that Sima Lun's cause was hopeless. Sima Yong knew of Sima Jiong's suspicion, and started a conspiracy; he invited Sima Ai the Prince of Changsha to overthrow Sima Jiong, believing that Sima Ai would fail; his plan was then to start a war against Sima Jiong in conjunction with Sima Ying. Once they were victorious, he would depose Emperor Hui and make Sima Ying the emperor, and then serve as Sima Ying's prime minister. In winter 302, Sima Yong declared his rebellion, and Sima Ying soon joined, despite opposition from his strategist Lu Zhi (盧志). Hearing that Sima Ai was part of the conspiracy as well, Sima Jiong made a preemptive strike against Sima Ai, but Sima Ai was prepared and entered the palace to control Emperor Hui. After a street battle, Sima Jiong's forces collapsed, and he was executed. Sima Ai became the effective regent, but in order to reduce opposition, he submitted all important matters to Sima Ying, still stationed at Yecheng.

After Sima Jiong's death, Sima Ying became extremely arrogant as well, and trusted inappropriate persons, chief among whom was his servant Meng Jiu (孟玖). Even though Sima Ai submitted all important matters to him, he still considered Sima Ai an interference to his control of government and wanted to eliminate him. At the same time, Sima Yong, who had hoped that if Sima Ying became emperor he could then be prime minister, persuaded Sima Ying to again join him against Sima Ai. They started military action against Sima Ai in fall of 303, and while they had overwhelming force, their forces could not score a conclusive victory against Sima Ai. Sima Yong's forces were about to withdraw in spring 304 when Sima Yue the Prince of Donghai, the grandson of a great-granduncle of Emperor Hui, believing that Sima Ai could not win this war, arrested him and delivered him to Sima Yong's general Zhang Fang, who executed Sima Ai cruelly by burning him to death. Sima Ying became in effective control of the government, but continued to control it remotely from Yecheng.

As regent and crown prince

Sima Ying soon ordered Emperor Hui's second wife, Yang Xianrong, and his crown prince Sima Qin, deposed. Then, at Sima Yong's pre-arranged petition, Sima Ying was created the crown prince. He put people he trusted in charge of the defenses of Luoyang, while remotely controlling the government from Yecheng. Eventually, the officials in Luoyang tired of the situation, and they rose under Sima Yue's command in summer 304. Sima Yue, with Emperor Hui accompanying him, then attacked Yecheng. Sima Ying, after some initial hesitation, battled Sima Yue's troops and defeated him, forcing him to flee and capturing Emperor Hui. He did not return Emperor Hui to Luoyang, but kept him at Yecheng.

This gave Wang Jun (王浚), the commander of the forces in You Province (幽州, modern Beijing, Tianjin, and northern Hebei), with whom Sima Ying had prior disputes, an excuse to attack Sima Ying, and he did so, claiming that Sima Ying was improperly detaining Emperor Hui. Wang's forces were reinforced with ferocious Xianbei and Wuhuan soldiers, and Sima Ying's forces, in fear of their fighting abilities, collapsed, before they could be reinforced with Xiongnu forces under the command of Sima Ying's associate Liu Yuan. Sima Ying was forced to flee to Luoyang with Emperor Hui, now without troops to support him. (Upon hearing Sima Ying's collapse, Liu Yuan, instead of coming to Sima Ying's aid, declared independence from Jin and styled himself the Prince of Han, claiming descent (through a princess) from Han Dynasty, thus creating Han Zhao.)

Once Sima Ying arrived in Luoyang, he found the troops of his ally Sima Yong there, commanded by Zhang Fang. Instead of continuing to support Sima Ying, however, Sima Yong turned his back on Sima Ying and had him removed from his crown prince position, instead creating another brother of Emperor Hui, Sima Chi the Prince of Yuzhang, crown prince. Sima Ying was demoted back to being the Prince of Chengdu. Soon, Zhang forced Emperor Hui, Crown Prince Chi, and Sima Ying to move from Luoyang to Chang'an, safely under Sima Yong's control.

After removal as crown prince

After Sima Ying was removed as crown prince, the people of Yecheng nevertheless missed the days when he was considered a capable governor, under Lu's guidance. In 305, his former subordinates, the generals Gongshi Fan (公師藩) and Ji Sang therefore declared a rebellion, seeking to restore him. Sima Yong sent Sima Ying to try to pacify or suppress the rebellion, but while he was on the way to Yecheng, Sima Yue declared a rebellion with the ostensible goal of returning Emperor Hui to Luoyang, and Sima Ying was unable to progress to Yecheng; he instead returned to Chang'an. After Sima Yue defeated Sima Yong in 306 and welcomed Emperor Hui back to Luoyang, he put out an order for Sima Ying's arrest, and Sima Ying fled with his sons Sima Pu the Prince of Lujiang and Sima Kuo the Prince of Zhongdu, attempting to flee to Gongshi, when he was intercepted by Feng Song the governor of Dunqiu Commandery (頓丘, roughly modern Puyang, Henan) and taken to Yecheng. The defender of that city, Sima Xiao the Prince of Fanyang, imprisoned Sima Ying but did not wish to kill him. However, when Sima Xiao died later that year, his secretary Liu Yu, worried that there were still many of Sima Ying's supporters in the city, forged an edict ordering Sima Ying to commit suicide. His two sons were also killed with him. After Ji captured Yecheng in 307, he placed Sima Ying's casket on a wagon in his command train, and he would report all important decisions to Sima Ying's casket. After Ji was defeated in 308, Sima Ying's casket was thrown in a well, and his formal associates took it out of the well and buried it.

生平

封成都王

太康十年（289年）十一月甲申受封成都王，食邑十萬戶。後拜越騎校尉，加散騎常侍、車騎將軍。賈謐曾與皇太子司馬遹爭道。司馬穎在坐，厲聲指責賈謐：「皇太子國之儲君，賈謐何得無禮！」賈謐懼，由此派穎出任為平北將軍，鎮鄴城。後轉鎮北大將軍。

討伐趙王

永寧元年（301年），趙王司馬倫稱帝，升任征北大將軍，加開府儀同三司。到了齊王司馬冏起義兵反司馬倫時，司馬穎發兵響應，行軍至朝歌，有衆二十餘萬。先鋒趙驤先敗後勝下大破趙王軍。司馬穎於是渡過黃河，乘勝長驅直入。此時左將軍王輿與尚書廣陵公司馬漼領兵入宮殺孫秀等人，幽禁趙王倫，迎惠帝復位。司馬穎入京都時，誅殺司馬倫。同時派趙驤、石超等助齊王司馬冏在陽翟攻討虜將軍張泓，張泓見此投降。司馬冏此時才可率兵衆入洛陽，自以第一個舉兵討伐而專擅威權。司馬穎亦不領功，向惠帝說是大司馬司馬冏之功勛，托辭出宮，回鎮鄴城。

回鄴城後，惠帝下詔派兼太尉王粹賜司馬穎加九錫殊禮，進位大將軍、都督中外諸軍事、假節、加黃鉞、錄尚書事，入朝不趨，劍履上殿。司馬穎拜受徽號，辭讓殊禮九錫，又上表提及參與討伐的功臣盧志、和演、董洪、王彥、趙驤等五人，全部皆封開國公侯。司馬穎又上表請求運十五萬斛糧食解救受戰禍影響的陽翟居民，更接納慮志建議收殮黃橋戰死的八千士兵，又設立墓園、祭堂和記念戰功的石碑；並命河內溫縣長官埋葬司馬倫的一萬四千名戰死士卒。這些舉動使司馬穎的名望更高。

遙控朝廷

及後齊王冏驕侈無禮令人失望，成都王穎於是衆望所歸，望能改善國家。惠帝下詔喻司馬穎入朝輔政。司馬穎親信的宧官孟玖不想回洛陽，加上母親程太妃愛戀鄴都，於是司馬穎猶豫未決。同時司馬穎的義募軍隊想回到家鄉，他知義募軍隊不可留，所以遣散，以安百姓。太安元年（302年），司馬冏被長沙王司馬乂打敗並殺害，司馬乂掌權；司馬乂雖然總掌朝中大權，但事無巨細都會向鄴城的司馬穎報告和詢問，故此司馬穎實是遙距執掌朝政。

太安二年（303年），義陽蠻張昌因受不住新野王司馬歆的嚴法，聚眾數千人在荊州作亂，後更殺司馬歆。司馬穎拜表南征，所在人民都響應參軍。但不久張昌就被陶侃平定。司馬穎此時恃著功勛而驕奢，令百度弛廢，比司馬冏更差。司馬穎想胡作非為，但忌憚在朝內的兄長長沙王司馬乂；同時河間王司馬顒亦想奪權，邀請司馬穎與他組聯軍攻打司馬乂，於是就與司馬顒上表請誅羊皇后之父羊玄之、左將軍皇甫商等，並檄司馬乂回府第。自己則帶領著原本要攻打張昌的軍隊與司馬顒之將軍張方攻伐洛陽，以平原內史陸機為前鋒都督、前將軍、假節。司馬穎到朝歌，進軍屯河南。此時陸機戰敗，死者甚衆，孟玖亦誣陷陸機，司馬穎遂收斬陸機，夷其三族。其後與張方一同進攻洛城。但戰事維持數月，司馬乂軍奮力死戰，多次大破聯軍，死傷六、七萬人，張方亦打算撤退；同時常山人王輿合衆萬餘人，打算襲擊司馬穎。可是，司空司馬越卻害怕缺糧中的司馬乂軍會擋不住，與幾名殿中將領囚禁司馬乂到金鏞城，向司馬穎和司馬顒投降，後更送交張方殺害，王輿則被手下斬殺，全兵向司馬穎投降。司馬穎入洛陽後，因在朝野向來有威望，而且軍事實力強，入洛陽後被增封二十郡，拜丞相。司馬顒及後上表認為司馬穎應該成為皇位繼承人，於是廢去司馬覃皇太子之位，以司馬穎為皇太弟，丞相位置不變。

兵敗被廢

司馬穎獲大權後回他的根據地鄴城，繼續遙控政權，排場與皇帝可以比較，目無皇帝，處處展現其奪位野心，又任用孟玖，這令人民都大失所望，也給其他有野心的王有了討伐的藉口與機會。永安元年（304年），司空東海王司馬越與左衛將軍陳眕，殿中中郎逯苞、成輔及長沙王故將上官巳召集四方共討司馬穎，雲集了十多萬人，讓司馬覃復位，並帶惠帝親征。司馬穎知道後大為驚震，想要逃跑，其部下勸其不要，司馬穎就召集各人商量對策。東安王司馬繇認為皇帝親自來討伐，應該投降請罪，司馬穎不肯。司馬王混及參軍崔曠則勸司馬穎迎戰，司馬穎贊同，派遣奮武將軍石超率五萬兵馬到蕩陰（今河南湯陰）。陳眕的兩位弟弟陳匡與陳規親自到司馬越軍中，聲稱鄴城中司馬穎部下聽到皇師到來已經離散。東海王司馬越信以為真，軍隊於是防備鬆懈。石超趕到蕩陰，大敗司馬越軍，甚至射傷惠帝，左右都爭相逃命，將惠帝遺下草地上。石超於是把晉惠帝送到鄴城，司馬穎改年號為建武，殺死之前勸司馬穎投降的東安王司馬繇。司馬越在兵敗時先逃到下邳，當時的徐州都督、東平王司馬楙不接納他，司馬越就逃回其封地東海（今山東郯城北）。司馬穎以同是宗室兄弟的名義，下令寬恕司馬越，要招他回朝，司馬越不應命。陳眕和上官巳則帶太子司馬覃守洛陽，司馬顒當時也派遣張方率兵二萬助司馬穎。但大軍到達時司馬越軍已敗，就乘機進駐洛陽，上官巳派苗願抵抗張方但失敗，司馬覃卻襲擊上官巳，上官巳和苗願逃走，司馬覃則向張方投降，再次被廢。

司馬越的親弟弟并州刺史東瀛公司馬騰及安北將軍王浚，殺死司馬穎所置的幽州刺史和演。於是司馬穎出兵討伐司馬騰。司馬騰與王浚結合外族烏丸人羯朱等勢力共同攻擊司馬穎。司馬穎派遣新選的幽州刺史王斌及石超、李毅等人抵抗司馬騰等人，被羯朱打敗。戰敗的消息傳到鄴城後，人心惶惶，官僚士兵相續逃跑。司馬穎甚是恐慌，與幾十個將軍連同晉惠帝連夜逃到洛陽。羯朱的軍隊一路追趕司馬穎等人到朝歌，追不上才放棄。洛陽當時由司馬顒的部將張方控制，張方又挾持晉惠帝，司馬穎等人到司馬顒的根據地長安，司馬顒同時廢除司馬穎的皇太弟地位，要司馬穎離開朝廷回其封地。司馬顒自行選置百官，改秦州為定州，改元永興，並以豫章王司馬熾任皇太弟。司馬顒又讓晉惠帝下詔，要立遠在東海的司馬越為太傅，要司馬越回朝與太宰司馬顒共同輔政。司馬越不受。

歸北被殺

司馬穎被廢後，河北人都思念他，他的舊將公師籓、汲桑等人慾起兵迎接司馬穎。司馬顒見到司馬穎還有人支持，於是復拜司馬穎為鎮軍大將軍、都督河北的軍事，給兵千人，讓其回去鎮守鄴城。光熙元年（306年），司馬穎到達洛陽，但還沒回到封地時，司馬越討伐司馬顒的軍隊就來到，接連擊敗司馬顒屬下劉喬、樓褒、王闡等軍，向長安進發。司馬穎則逃到關中。此時司馬越攻陷長安，司馬顒出逃，司馬越等人帶惠帝回洛陽，司馬穎則從華陰經武關出新野。此時有詔令命鎮南將軍劉弘和南中郎將劉陶捉拿司馬穎，司馬穎因而拋棄母親和妻子，與兒子司馬普及司馬廓坐馬車回朝歌，收合數百將士，想投靠支持他的公師藩。途中被頓丘太守馮嵩所捕獲，送到鄴城，被范陽王司馬虓幽禁，但是並沒有加害於他。一個多月後，司馬虓暴斃，司馬虓的長史劉輿見到司馬穎在鄴城很有威望，憂慮留住司馬穎成後患，就秘不發喪，而且令人裝扮台使，假稱詔晉惠帝賜司馬穎死。司馬穎被看守他的人田徽縊死，時年二十八。他的兩位兒子也被殺。

司馬穎死後，官屬爭相奔散，惟獨盧志隨從不怠。其後汲桑殺害東贏公司馬騰，號稱為穎報仇，於是起出司馬穎的棺木，帶著它行軍，每有事都啓奏司馬穎，以行軍令。後來汲桑被打敗，放棺木於舊水井中。司馬穎舊臣收了棺木，改葬于洛陽，晉懷帝加縣王禮節。

司馬穎死後數年，開封地區有傳司馬穎有一個十餘歲的兒子，流離在百姓家，東海王司馬越遣人殺了他。永嘉年間，東萊王司馬蕤過繼其子司馬遵為司馬穎後嗣，封華容縣王。

家庭

母

程才人，被晉武帝封為才人，後為成都國太妃

妻

樂廣女

後代

• 司馬普，司馬穎兒子，廬江王，與司馬穎一同被殺。

• 司馬廓，司馬穎兒子，中都王，出繼司馬演，與司馬穎一同被殺。

• 司馬遵，東萊王司馬蕤之子，過繼了給司馬穎，封華容縣王，作為司馬穎後嗣。