In 1914 Cameron was elected to the executive of the Labour Party, a position he was to retain for many years.[3][7] In 1917 he was appointed by the Coalition Government to be one of the Scottish members of the Commission on Industrial Unrest.[8] In 1918 he again failed to be elected to parliament, this time at Woolwich West.[9]
In 1920 Cameron was part of the Labour Party delegation to the Second International in Geneva.[10] He was elected chairman of the Labour Party for 1920/21.[4] In 1925 ill health led to his resigning from his posts as representative to the Socialist International and general secretary of the woodworkers' union.[4][11]
At the 1929 general election Cameron finally succeeded in being elected, becoming MP for Widnes. He was however defeated at the next election in 1931 when there was a large swing against Labour.
Cameron retired from politics, and at the time of his death in a London hospital in 1944, was described as a building contractor.[3]