At the 1920 election proportional representation was introduced and the Yass electorate was absorbed into an expanded multi-member electoral district of Cootamundra, and he won a seat, helping to defeat the former Labor leader, turned Nationalist William Holman.
In 1920, proportional representation was introduced in the election, and Yass's constituents were incorporated into a larger electoral district encompassing Cootamundra. This led to his election victory, which helped topple former Labor leader William Holman, who had switched to the Nationalist party.