Born in Bow, London, Watts became a compositor and joined the Social Democratic Federation (SDF).
In 1904, he became a member of the Board of Guardians in Poplar, a post he held until his death.
After the SDF became the British Socialist Party, Watts became a leader of the majority anti-war faction, and was elected to the party executive as Treasurer, alongside Albert Inkpin and John Maclean.
He was a supporter of the October Revolution and of the formation of the Communist Party of Great Britain (CPGB).
[1] In 1919, Watts was elected as a Labour Party member of London County Council in Battersea North, and in 1922 he was re-elected for the CPGB.