McCarthy had enormous physical strength and was a fitness fanatic who enjoyed training in an era where it was unusual to do so. He walked five miles to work every day and joined Collingwood from Fairfield.
He helped win the 1919 flag for Collingwood as the foil for No.1 ruckman Les Hughes. He skippered that side and had played in the flag sides of 1917 and 1919 as well as the runner-up team of 1918.
He captained the side in 1919, 1921 and 1922. McCarthy was a great shepherder, a fine mark and kick and represented Victoria five times including the captaincy of the carnival side in 1921.
He went to Footscray VFA as playing coach in 1925 for a huge sum at the time of 400 pounds and Collingwood rigidly stuck with its policy of not making special deals with players.
He led the Bulldogs into the League and was revered at the club. Business forced him to give away the game. He handed over the coaching role in 1926, but continued as captain for the remainder of the season.