He became active in the Labour movement, leading a strike at Day Dawn in 1896, and becoming a workers' advocate before the State Arbitration Court for many unions.

He contested the Western Australian Legislative Assembly seat of Mount Magnet in the election of April 1901, but was defeated by Frank Wallace.

On 10 December 1901, Holman was elected to the Legislative Assembly seat of North Murchison in a ministerial by-election, defeating Frederick Moorhead.

He was Chairman of Committees in the Legislative Assembly from 1 November 1911 to 22 March 1917, and later acted as secretary and whip for the Parliamentary Labor Party.

His daughter, May Holman, was elected to the Legislative Assembly in his seat, becoming only the second woman to enter an Australian parliament, and the first for the Labor party.