At a time when Australian concert artists were relatively unknown in Europe, he dazzled the salons of royalty, aristocratic patronage and privilege in London, Paris and the French Riviera during the 1920s and 1930s.
His early experiences in the travelling silent cinemas of the Australian outback, alongside music hall and vaudeville performances, provided an unconventional foundation for his career as a concert pianist.
Cahill became a protégé of Dame Nellie Melba and performed for kings in Southeast Asia and maharajahs in India.
He was also invited for lessons by the pioneering pianist Alfred Cortot and had connections with notable figures such as the conductor Wilhelm Furtwängler, the pianist-statesman Ignacy Paderewski, and the composer Percy Grainger.
Cahill's concert tours in Nazi Germany ended a romance and musical collaboration with the Austrian Jewish violinist Sabine Adler.