[3] Fergus attended Maribyrnong College, a sports secondary school in Melbourne.
[3] A bowling all-rounder, O'Neill plays for Melbourne in Victorian Premier Cricket.
[4] In the 2021–22 season he received the Paul Sheahan Club Champion Award for his all-round performance, averaging 19.31 with the ball and 42.33 with the bat that year.
[5] O'Neill's performances in Premier cricket earned him a List A debut for Victoria later that season, as well as a first-class appearance for Victoria the following season in which he took four wickets on debut, including the wickets of Australian Test players Alex Carey, and Travis Head (twice).
[6] In Victoria's victory over South Australia in the 2023–24 Sheffield Shield, he took five wickets in each innings.