Born in Oadby in Leicestershire, Winterton was educated locally, then at the Borough Road College in Isleworth, where he qualified as a teacher.
After working in teaching, in 1920, he became a journalist on the Daily Herald, spending nine years at the paper.
[1] Winterton joined the Independent Labour Party (ILP) in 1911, and in 1917 he founded a new branch in Richmond-upon-Thames.
[2] The ILP was affiliated to the Labour Party, for which he stood unsuccessfully in Loughborough at the 1923 and 1924 general elections, before finally winning the seat in 1929.
[1] He was father of the journalist and crime fiction author, Paul Winterton.