Sitting as a Conservative, Winterton slowly rose through the ranks, later achieving ministerial office as Under-Secretary of State for India in 1922, a post he held until 1924.

Winterton did not hold office in the National Governments headed by firstly Ramsay MacDonald and then Stanley Baldwin.

In this role he proved a noted failure, especially in a heated debate in May 1938 which led to Chamberlain concluding that the Secretary of State for Air must be an MP.

The following year he was dropped from the Cabinet and served in the marginal post of Paymaster General before leaving the government altogether.

In 1952 he was created Baron Turnour, of Shillinglee in the County of Sussex, in the Peerage of the United Kingdom, which gave him a seat in the House of Lords.