[2][3] A member of the Communist Party of Great Britain in his youth, he left in the early 1930s, describing it as an "intellectual straitjacket".
He was elected to the General Council of the Trades Union Congress in 1947, serving until 1965, and became the President of the Trades Union Congress in 1959.
[5] From 1952, he also served as Chairman of the London Trades Council.
[2] In 1964, Willis led the Compositors into a merger with the Typographical Association to form the National Graphical Association, of which he served as joint general secretary until 1969.
[5][6] He took a leave of absence from 1965 to 1967 to serve on the National Board for Prices and Incomes.