Willcock became an active and enthusiastic member of the
Labor Party (ALP), holding various offices in the Geraldton branch of the Engine Drivers', Firemen's and Cleaners' Union, and representing them at Federal conferences. From 1914 to 1917 he was President of the Geraldton District Council of the ALP, and he was a
Justice of the Peace from 1915. On 14 April 1917 he contested the
Western Australian Legislative Assembly seat of Geraldton in a
by-election occasioned by the resignation of
Edward Heitmann, but was defeated by
Samuel Elliott. Five months later he won the seat in the
general election of 29 September 1917. He was soon made a member of the executive of the
Australian Workers' Union, and became secretary of the
Parliamentary Labor Party. On 16 April 1924, Willcock was appointed Minister for Railways and Justice and Minister for Police in the
Collier ministry. He held the Police portfolio until 25 June 1928, and the Railways and Justice portfolio until the defeat of the Collier government on 23 April 1930. From 1927 to 1930 he was deputy leader of the Parliamentary Labor Party.
Premier of Western Australia When the Labor party returned to power under Collier on 24 April 1933, Willcock resumed as Minister for Railways and Justice, and was also given the Education portfolio. He relinquished the Education portfolio on 26 March 1935, when he was reappointed deputy leader. On 19 August the following year, Collier stepped down as premier and leader of the Labor Party, and the following day Willcock was appointed his successor. Relinquishing the Railways and Justice portfolio, he took the offices of Premier,
Treasurer and Minister for Forests. He dropped the Forests portfolio on 9 December 1943, but held the other offices for nearly nine years, resigning for reasons of ill health on 31 July 1945. During his time as Premier of Western Australia, Willcock represented Western Australia at the
coronation of King George VI and Queen Elizabeth in May 1937. He was known for his "disarming modesty".
Retirement After resigning as premier, Willcock retired to the backbenches until the general election of 15 March 1947, at which he did not re-contest his seat. He died on 7 June 1956 at St John of God Hospital,
Subiaco, Western Australia, and was buried in
Karrakatta Cemetery.
John Willcock College (opened as John Willcock Senior High School), established in
Geraldton in 1975, was named after Willcock until it was renamed Champion Bay Senior High School. ==Personal life==