Born in Honiton, Bowerman moved to Clerkenwell in London at an early age. On leaving education, he worked as a jeweller and then a compositor. In 1872 he briefly worked for Hour newspaper before moving to the Daily Telegraph. He joined the London Society of Compositors in 1873 and became its General Secretary in 1892, a post he held until 1906.
In 1893, Bowerman joined the Fabian Society, and in 1897, he was elected to the Parliamentary Committee of the Trades Union Congress, the body which later became the General Council. In 1901, was elected as a Progressive Party alderman on London City Council, a position he held until 1907.
Bowerman was the President of the TUC in 1901, and the Secretary of the Parliamentary Committee from 1911 until 1921, when he became the organisation's first General Secretary. He retired from the post in 1923.