[1] He became a legendary figure thanks mainly to a fictionalised account of his life in Frank Hardy's novel Power Without Glory, which was also made into a television series.

Losing his job in the 1890s depression, he commenced a successful horse-racing gambling venture at his Johnston Street totalizator, which eventually earned him £20,000 per year (A$2,646,000 in 2021 terms).

Due to the fact that Hardy was a member of the Communist Party of Australia, the book, and its criticisms of Wren, became politically embroiled in the anti-communist culture of the Cold War.

Hugh Buggy's The Real John Wren (1977), with a foreword by Arthur Calwell, Federal Parliamentary Labor Party Deputy Leader, was also very favourable.

His son Anthony committed suicide after being disinherited following an argument with Wren, while his daughter-in-law Nora and grandchildren only received a meagre allowance.