He Jin's family hailed from Yuan 宛 (modern Nanyang 南陽, Henan). When his sister became an imperial favourite, He Jin was appointed court attendant (langzhong 郎中) and then Leader of the palace gentlemen (huben zhonglangjiang 虎賁中郎將), in which position he acted as governor (taishou 太守) of the commandery of Yingchuan 潁川.
In 180, his sister was made empress, and He Jin was subsequently promoted to palace attendant (shizhong 侍中) and metropolitan magistrate (yi 伊) of Henan. When the Yellow Turban rebellion 黃巾起義 broke out, He Jin was appointed Great general (da jiangjun 大將軍), defending the capital. For these efforts he was given the title of Marquis of Shen 慎侯.
Yuan Shao, nevertheless, was able to slaughter the eunuchs and thereby unintentionally evoked the total disintegration of the central government of the Later Han dynasty.