He was the Mayor of the Pitcairn Islands, a British dependency in the Pacific Ocean, from 7 December 1999 to 30 October 2004. As such, he was the local head of government of what is the smallest generally recognized country in the world with regard to population, as the Pitcairn Islands have a total population of only 45, as of December 2005. He also acts as the island's supervising engineer/mechanic, dentist and X-ray technician, and as coxswain of the longboat, which is described as Pitcairn's umbilical cord to the outside world. He was formally dismissed from office on 30 October 2004, following his rape conviction on 24 October.
Christian is a patrilineal descendant of Fletcher Christian, leader of the mutineers in the late 18th century on the HMS Bounty, a story told in the 1932 Nordoff and Hall novel Mutiny on the Bounty, and several subsequent motion picture versions. He is the son of Ivan Roa Christian and Verna Carlene "Dobrey" Young a descendent of Ned Young. Ivan Roa Christian is the son of Richard Charles Edgar Christian who is the son of Francis Hickson Christian. Public respect for his lineage gave him considerable de facto influence long before he held political office, first as a member of the Island Council in 1976. He again served on the Council in 1982, and was briefly Chairman of the Internal Committee (considered the second-most influential political position on the island) in 1985. He was to hold this position again in 1991 and 1992, 1994 and 1995, and 1998 and 1999, when he was elected as the island's first Mayor. The title was new but the office was not: the Mayor had previously been known as the Magistrate.
He married Olive Jal Brown in 1972 and they have four children. Trent, Randy, Shawn and Tania.
In 2004, Steve Christian, along with six other men, was tried on charges of rape and child sexual abuse by the Pitcairn Supreme Court. Over the course of the trial, it was alleged that Christian repeatedly raped or assaulted a number of island women, including some children, over a period of several years — using the remoteness of the island, and his position of power to coerce their silence. Christian denied all accusations of impropriety, but admitted having consensual sex with several of his accusers. Christian pleaded not guilty to all charges of rape and indecent assault, but on 24 October 2004, he was convicted of committing five rapes between 1964 and 1975. (He was acquitted of a sixth rape charge and of four indecent assault charges).
On 8 November 2004, Christian's sister Brenda, the island's sole police officer, was elected by the Island Council to succeed him in an interim capacity, pending elections scheduled for 15 December, when Jay Warren, the acquitted former magistrate, was elected mayor.