Mid-Joseon civil official and merit subject who led the Injo Restoration coup

| Life | 1557 ~ 1633 |
| Era | 조선 |
| Clan | 연안 이씨 |
His courtesy name was Okyeo and his pen name was Mukjae; his clan seat was Yeonan. A disciple of Yi I and Seong Hon, he passed the civil examination in 1603 and served as magistrate of Ansan and Baecheon. During the Imjin War he served as a supply-and-recruitment officer, procuring cattle, horses, provisions and soldiers for commander Yu Seong-ryong. Implicated in a court case, he was exiled from 1616 to 1619. In March 1623 he led the coup, together with Kim Ryu and Sin Gyeong-jin, that deposed King Gwanghae and enthroned Neungyanggun (King Injo) — the Injo Restoration — for which he was ranked first-class Merit Subject (Jeongsa Gongsin) and ennobled Prince of Yeonpyeong. His two sons, Yi Si-baek and Yi Si-bang, also took part and were likewise honored as merit subjects.
He subsequently held posts including Royal Guard Commander, Second Minister of Personnel, Third State Councillor, Inspector-General and Second State Councillor. During the 1627 Manchu invasion he argued for peace negotiations, and by 1631 he had risen to Minister of Personnel, remaining an active voice on defense and reform to the end of his life.
His son Yi Si-baek rose to chief state councillor, and Yi Si-bang also served as a minister.