By trade he was a bricklayer (as were George Hicks and F. K. Cadman) and after 1913 was on the teaching staff at the LCC School of Building at Brixton.

Fitzgerald had been active in the Social Democratic Federation from around the turn of the century, being a public speaker and a delegate to SDF Conferences in 1901 (Central branch) and 1902 (Burnbank).

Whilst a member of the SDF he had taught classes for the party on Marx's Capital, where one of his students was Thomas A. Jackson, who described him as "very nearly the best-read man I have ever met".

[1] Along with Horace Hawkins he was expelled by the SDF at its 1904 Conference at Burnley, an action which led to the formation of the Socialist Party of Great Britain.

Harry Wicks described Fitzgerald in his book Keeping My Head: …fearless in debate, he was so confident in his own party case that he would take on anyone, be they small fry or big cheese.