Recruited from Barwon in the Geelong & District Football Association, Hagger played as a key position forward and was known for his high marking and ability to kick goals from difficult angles. Named captain-coach of Geelong in 1924, Hagger was captain for only one season, handing the job over to Cliff Rankin. In 1925 Geelong won the premiership and Hagger was the League's leading goalkicker, with 78 for the season. He also regularly played for Victoria in interstate matches. At the 1924 Hobart Carnival, Hagger, playing for Victoria against Western Australia, kicked seven goals in Victoria's eight point win. Late in the match Hagger was momentarily knocked out but recovered in time to refuse to leave the ground after a stretcher had been called.
Hagger had a reputation for being very talkative during gameplay. He also worked as a cartoonist for The Sun News-Pictorial.