He unsuccessfully contested the Walthamstow West constituency at the 1922 and 1923 general elections, before winning the seat at the 1924 general election, narrowly defeating the sitting Labour MP Valentine McEntee. During the 1924-29 parliament which was dominated by a Conservative majority, Crawfurd worked closely with a group of radical Liberal MPs that included: William Wedgwood Benn, Percy Harris, Joseph Kenworthy and Frank Briant to provide opposition to the government.
He failed to win the Walthamstow West constituency in the 1922 and 1923 general elections, but succeeded in the seat at the 1924 general election, defeating Labour MP Valentine McEntee. During his tenure from 1924 to 1929, Crawfurd collaborated with a group of progressive Liberal MPs, including William Wedgwood Benn, Percy Harris, Joseph Kenworthy, and Frank Briant, to oppose the Conservative government.