Newspaper veteran Bellew wrote for The Argus, the Melbourne Herald, the Daily Telegraph, and the Sydney Daily News. He became Chief of Staff of The Daily Telegraph and the Daily News. 

In 1947, Bellew founded comic publisher Atlas with George Warnecke and Clive Turnbull. Bellew created the company's first comic, Captain Atom, and wrote the first 20 issues under the pseudonym 'John Welles'. Despite launching with a full colour Australian comic, Atlas' output was largely US and UK black-and-white newspaper strip reprints. Atlas also published pulp and men's magazines, such as Zowie, Fun and Frolic. Atlas ceased operation in 1958.

Bellew also became the editor of Tomorrow, a sensationalist tabloid focused on attacking capitalist conglomerates and the opponents of British socialism. Amongst its frequent targets were the Liberal Party and Robert Menzies.