During the 1940s and 1950s, ABC employed a staff pianist by the name of Margot Sheridan, who accompanied singers, instrumentalists and played in ensembles on radio, and later in television.

Following a successful audition at ABC in the 1950s (for which she played her own arrangement of Tico Tico), Peggy started appearing regularly as accompanist and ensemble pianist on broadcasts, while simultaneously playing with her trio in Melbourne nightspots, accompanying cabarets by artistes such as a young Barry Humphries, Juanita Hall and a one-off, impromptu performance by Frank Sinatra.

It was during this spell that she played for - and rubbed shoulders with - artistes like Sammy Davis Jr., Tony Bennett, Dame Cleo Laine, Dizzy Gillespie, Oscar Peterson, Marion Montgomery, and Helen Merrill, while renewing an old and rather special friendship with legendary bass player, Ray Brown.

During this time she met and teamed up with double bass player Ricky Fernandez and drummer Rudi Celerio, with whom she became "The Peggy O’Keefe Trio."

At the end of this contract, they transferred to Reo Stakis’ Chevalier Casino (where they were augmented to become "The Peggy O’Keefe Quartet" by the addition of Jimmy Feighan on vibraphone).

During this time, this venue and programme‘s popularity was acknowledged by the release of an LP, Mood Chevalier (EMI/Waverley ZLP2083), which featured the quartet with guests Ian McHaffie on guitar and Dougie Kerr on trumpet.

Contrary to a popular misconception, O’Keefe was never featured on STV’s "One O’Clock Gang:" the resident ensemble was actually The Tommy Maxwell Quartet.

O'Keefe continued to work leading her trio for corporate functions, as a fixture at Sunday lunch in Gleneagles Hotel and as accompanist to Scottish entertainers (most notably Peter Morrison, Anne Lorne Gillies and Gordon Cree.)