[3] In 2009, the year he became eligible for the AFL Draft, Gunston was selected for the Sandringham Dragons, a TAC Cup team.

He refused to participate in the finals series for Central District, choosing to return home to Victoria before the end of the SANFL season.

[10] Gunston played in the 2013 Grand Final against Fremantle, and was one of the best players on the ground, kicking 4 goals to be the leading goalkicker in the match and finishing second in the Norm Smith Medal count to teammate Brian Lake.

[11][12] Gunston played an important role as key forward in 2014, finishing with a career-high 58 goals for the season[13] and earning his second premiership as Hawthorn triumphed in the 2014 Grand Final.

[17] In 2016, Gunston was forced to take on new roles due to the season-ending injury received by Jarryd Roughead, occasionally moving into the centre.

As both a result of this and a large number of injuries suffered by Hawthorn's key defenders, Gunston was moved into the backline, where he significantly improved his performance.

[24] His forward partnership with Breust was not as effective as the previous season, with the pair kicking only a combined 60 goals between them, and Hawthorn missed the finals.

At the conclusion of the 2022 AFL season, Gunston expressed a desire to move to the Brisbane Lions as a free agent.

However, in order to avoid diluting their free agency compensation for losing Daniel McStay, the Lions instead sought to trade for Gunston, ultimately acquiring him on 11 October in exchange for AFL draft pick 48 and a future fourth-round selection.