[1] Uren played rugby league for Manly Warringah in his youth and was a strong competitive swimmer.

Uren had an early career as a professional boxer,[2] and challenged for the Australian heavyweight championship against Billy Britt.

Uren was deployed to Timor and was a prisoner of the Japanese from 1942 to 1945, during which time he worked on the Burma Railway and served with Edward "Weary" Dunlop.

[5] Uren was later transferred to Japan where he witnessed the distant crimson sky that resulted from the explosion of the US atom bomb on Nagasaki.

On return, Uren worked as a Woolworths manager at Lithgow which led to being inspired to join the Australian Labor Party after attending Ben Chifley's funeral.

[citation needed] Uren and his wife Patricia moved to Guildford, in Sydney's west, in the late 1940s, and established two small retailing outlets on the corner of Chetwynd Road and Hawksview Street, West Guildford to gain the financial independence to pursue a political career.

In Sydney, Uren promoted the restoration and re-use of derelict inner city areas such as the Glebe Estate and Woolloomooloo, the reclamation of Duck Creek and the creation of the Chipping Norton Lakes Scheme.

Uren succeeded Jim Cairns as leader of the ALP Left, and favoured Bob Hawke's rise to the Labor leadership.