He was born at Windsor to William Walker and Henrietta Medora, née Cooper.
After attending Windsor Grammar School and Cooerwell Academy at Bowenfels he worked for the Commercial Banking Company of Sydney until he was articled in his father"s legal firm. In 1899 he was admitted as a solicitor and became a partner in his father"s firm. He also entered the military, rising to become a major in the Australian Light Horse.
In 1917 he was elected to the New South Wales Legislative Assembly as the independent member for Hawkesbury.
With the introduction of proportional representation in 1920 Walker, having joined the Nationalists, was elected as one of the members for Cumberland, representing that seat until single-member districts were reintroduced in 1927 and he resumed his old seat of Hawkesbury. He died later that year at Windsor.