Hawthorn led by 23 points after a fast-paced but low-scoring first half before Fremantle narrowed the gap to just 3 midway through the third quarter. But late goals by Luke Breust and Bradley Hill allowed the Hawks to hold on and to claim their first AFL title since 2008 in front of more than 100,000 fans at the Melbourne Cricket Ground.
The win allowed the Hawks to finally shed a reputation as under-achievers after their upset loss to Sydney in last year's Grand Final and their three-point defeat to Collingwood in the 2011 preliminary final.
They are the only team to have won at least one premiership per decade since the 1960s, accumulating 11 titles since 1961.
A total of 10 Hawthorn players became two-time premiership winners, including Shaun Burgoyne, who won with Port Adelaide in 2004 and superstar Lance Franklin, who kicked one goal in the first quarter.
Coach Ross Lyon, who led Fremantle into the premiership decider for the first time in their 19-year history, remained without a win in four Grand Finals. He guided St. Kilda to the premiership deciders in 2009 and 2010, when a replay was needed to find the champion.
Hawthorn coach Alastair Clarkson won the premiership for the second time in his nine-year reign.
Gunston's three first-half goals were crucial in a close-fought match, in which Fremantle didn't kick their first goal—through Tendai Mzungu—until the 12th minute of the second quarter.
By that stage Hawthorn had four goals and Gunston strengthened their position when he followed Mzungu's major with his third goal.
In a match that was occasionally made scrappy by wet conditions, Fremantle dominated the ruck in the first half through Aaron Sandilands without turning possession into points. Midfielders David Mundy, Nathan Fyfe, Michael Barlow and Stephen Hill led Fremantle's strong start to the third quarter when it kicked five of the first seven goals.
But Fremantle paid for their inaccuracy when thy missed several late chances in the final quarter.
Brian Lake won the Norm Smith Medal as best player of the match, claiming his first premiership medal after losing three preliminary finals with the Western Bulldogs.
Jordan Lewis, Josh Gibson, Grant Brichall and Cyril Rioli, who made seven tackles, were also prominent for Hawthorn while Fremantle tagger Ryan Crowley kept Sam Mitchell to just 12 touches.