He began serving with the Government of Johor at 16, working as a trainee clerk in the Office of the Minister Raja
Temenggong Daeng Ibrahim. In 1856 he was appointed clerk in the Office of the Minister, and then he served as deputy for the
Menteri Besar until 1882. He was Sultan Abu Bakar's escort in the latter's first trip to Europe in 1866. He took office in 1885 when Temenggong
Abu Bakar made himself
sultan and created a bureaucratic administration for
Johor. During his term as Chief Minister, Jaafar was tasked with carrying out state administration when Abu Bakar went overseas. His residence for most of the latter part of his life was the Istana Bukit Senyum which was built in 1883. A high school behind the palace – Sekolah Dato' Jaafar – is named after him. In 1904 he was appointed by Sultan Ibrahim, Abu Bakar's son and successor as regent. ==Personal life==