The highly-rated midfielder will be with the Giants until at least the end of the 2029 season after resisting overtures to return to his Victorian home.
Off-contract at the end of this season, the 21-year-old reportedly turned down a monster $17 million, 10-year deal from St Kilda to remain in NSW.
"Finn has shown over his first three seasons that he's an immense young talent in this competition and we are rapt to sign him to a new four-year deal," football boss Jason McCartney said in a club statement.
"A player of Finn's talent and age meant there was always going to be huge immense interest from other clubs and it's fantastic that he's re-committed to the club as we see him as a huge piece of our future.Â
"Finn can see the bright future of the club under Adam Kingsley and wants to be part of the success that we strongly believe is on the horizon."
Callaghan has been instrumental for the Giants in the engine room alongside Tom Green, averaging 23 disposals, 3.6 tackles, and 3.4 clearances per game last year - his third season at AFL level.
He is the latest in a long line of GWS stars - including Jesse Hogan, Brent Daniels, Aaron Cadman and Sam Taylor - to sign contract extensions.
Left burning after a straight-set finals exit, GWS will kick off their 2025 season by hosting Collingwood at Engie Stadium on March 9.
9°C