Hailing from North Queensland, John O'Shea began training in 1999 after working with some of the leading Sydney stables including Bart Cummings and Gai Waterhouse.
it was in 2002 that John O'Shea trained his first Group 1 winner when Shot Of Thunder won the Toorak Handicap at Caulfield which started a run of success for the stable.
Continuing to rise through the Sydney training ranks, O'Shea took out Group 1 races with the likes of Private Steer, Charge Forward and Racing To Win, the latter winning five majors between 2006 and 2008.
In May 2014, O'Shea took over as head trainer of Sheikh Mohammed's Darley team, rebranded as Godolphin later that year.
O'Shea trained for Godolphin until early 2017 when he quit the post to take a break from racing, saddling up over 550 winners and 10 Group 1 successes during his time in charge.
O'Shea returned to the Randwick training ranks at the start of the 2017/18 season.