Tom Kelly joined the Universal Credit Union in 1949, by 1957 he was Chairman. In 1973 he left to manage the Railways Staff Credit Union, which he had created in 1966. Between 1960 and 1972 he was a director of the NSW Credit Union League and from 1965 to 1968, a member of the Board of the Credit Union National Association in America. In 1967 he became editor of Quest, the credit union newspaper.
He convened the inaugural meeting of the Australian Federation of Credit Union Leagues in 1966 and represented Credit Unions on the Committee of Management of the Co-operative Federation of NSW Ltd, of which he was also the Vice Chairman, 1969-1971. In 1985 he was co-founder of the Australian Credit Union Historical Co-operative, now the Archives and was its voluntary secretary-manager for 18 years.
Tom Kelly provided an oral history interview for the credit union movement in 1996 when he was interviewed by Richard Raxworthy.