Starting out as a  in the lower grades at the Mascot Juniors RLFC, Treweek was moved into the second-row upon reaching first grade and won five premierships with South Sydney, captaining the side in the 1931 and 1932 premiership victories.
Starting out as a player in the lower grades at the Mascot Juniors RLFC, Treweek was promoted to the second-row upon reaching first grade and won five premierships with South Sydney, leading the side in the 1931 and 1932 premiership victories.