Farquharson played football for Oakdale and Abertillery Town before being spotted by Football League side Cardiff City in 1922 for whom he made his professional debut that May. He helped the side finish as runners-up in the First Division during the 1923–24 season and reach the 1925 FA Cup Final. In 1927, he was a member of the Cardiff City team that became the only non-English side to win the FA Cup. He remained with the club until 1935, winning the Welsh Cup on four occasions and the FA Charity Shield once. Farquharson played in 445 Football League matches for Cardiff, which remained a club record until 1985.