[5] Recruited from prominent junior club Port Melbourne Railway United,[6][7][8] Thomas played on the wing.
[9] He played in thirteen home-and-away games (i.e., no Finals) over two seasons – the first, replacing George Bower, was against Fitzroy, at the Brunswick Street Oval, on 9 May 1914 – coming in and out of the South Melbourne team on multiple occasions during the two seasons.
Employed as a fireman with the Victorian Railways, he enlisted in the First AIF on 24 August 1915 and departed from Melbourne aboard HMAT Kabinga (A58)[10] on 8 May 1916.
[14][15] Serving in the same unit as Claude, Rupert Clarence Thomas was killed in action, in France.
[16] On 5 July 1918,[17] Thomas was lying in a trench near Vaire Wood, during the Battle of Hamel when a piece of shrapnel from a German shell glanced off the parapet and struck his ammunition pouch, "the contents of which exploded and blew a hole right through him, killing him instantly".