The Hawks ended the Cats' hopes of back-to-back premierships with a strong showing, winning 14.15 (99) to 11.12 (78).
The Cats held a 13-game winning streak heading into the premiership decider but were overwhelmed by a Hawks unit in total control from the outset, who claimed their first flag since 2001.
A number of listed Hawthorn players pressed their claims for a spot in next week's AFL Grand Final against Fremantle, with Jonathan Simpkin, Matt Spangher, Shane Savage, Taylor Duryea and Kyle Cheney all strong contributors.
Simpkin, who gathered 26 disposals and kicked two goals, won the Norm Goss Medal for being best afield.
Geelong entered the match favourites to again raise the cup, but Damian Carroll's side also had form up its sleeve, having won its past seven games by an average of seven goals.
Their balance across the ground was evident in the win.
Talls Luke Lowden, Sam Grimley and Tim O'Brien were dangerous close to goal, Mitch Hallahan, Simpkin and Will Langford broke the lines through the midfield, and Cheney and Spangher were tight in defence.
After being in control for most of the day, Box Hill's victory was well earned. It gained the early ascendancy, kicking seven opening-quarter goals, and appeared too sharp and clinical for the Cats outfit.
But they could manage only two goals for the second quarter as the Cats stormed back, with forward Josh Walker a focal point with four goals to half-time.
Unfortunately for the Cats, however, that didn't extend beyond the main break, with Matthew Knights' side kept goalless for the quarter.
When veteran Hawk Michael Osborne snapped a goal on his left side from the pocket in the third term, it put the Hawks up by 16 points.
They kicked another immediately through Hallahan and kept chipping away, with a Simpkin major giving the Hawks a 31-point buffer midway through the quarter.
The premiership was all but secured when Grimley kicked a goal in the first 15 seconds of the final term, giving the Hawks a 39-point advantage.
Three late goals were little consolation for the Cats, who were outplayed and down on impact from their stars.
Playing in defence, Geelong's Mitch Brown repelled well, Mark Corrigan battled hard in the midfield, and Taylor Hunt gathered 21 disposals in between several heavy knocks.
GEELONG 4.3 7.6 7.7 11.12 (78)
BOX HILL HAWKS 7.2 9.4 12.10 14.15 (99)
GOALS
Geelong: Walker 4, Bathie 2, Burbury, Hartman, Kersten, Sheringham, West
Box Hill Hawks: Grimley 3, Murphy 2, Osborne 2, Simpkin 2, Hallahan, Iles, Lowden, Retzlaff, Savage
BEST
Geelong: Gleeson, Hunt, Corrigan, Walker, Brown, Smedts
Box Hill Hawks: Simpkin, Spangher, Hallahan, Iles, Langford, Litherland
