He was the oldest of four children born to Hazel "Wendy" Winter and Henry Alfred Jenkins.

Aged 33, Jenkins won ALP preselection for the resulting 1986 Scullin by-election ahead of former Casey MP Peter Steedman and future state government minister Theo Theophanous.

[4] He was described by the Canberra Times as "chosen as a compromise candidate by the old and new guards of Victoria's Socialist Left faction".

[7] He was elected by Labor caucus on 29 November 2007 to become the Speaker of the House of Representatives in the 42nd Parliament.

Although Speakers normally carry the courtesy title while in office 'the Honourable', Jenkins said his personal preference was that it not be used.