In 1912, he became an elementary school teacher in Durham, but he left in 1915 to serve in World War I.
[1] After the war, Shearman became active in the Labour Party, and at the 1922 UK general election, he unsuccessfully contested the Isle of Wight.
From 1927, he worked for the Workers' Educational Association, until 1946, when he was elected to London County Council as an alderman.
At the 1952 London County Council election, he switched to become a councillor, representing Deptford.
[1] In his spare time, Shearman served on numerous committees, including the Committee on Higher Education, Commonwealth Scholarship Commission, and as chair of the School Journey Association of London and the Metropolitan Examinations Board.