A ruckman, 209 cm tall and weighing 111 kg, Gawn is capable of contributing in both the ruck and forward line.

Knee and hamstring injuries hampered his first four seasons in the AFL before he moved into the number-one ruck position at Melbourne in 2015 along with selection for the 2016 All-Australian team.

[4][5] Following his father's recommendation, he played rugby union in Under-10s for Powerhouse RUFC in Albert Park, Victoria.

[12][13] He played a few matches at the end of the season for Melbourne's affiliate team, the Casey Scorpions, in the VFL Development League.

[14] After strong performances in the VFL for Casey in the first half of 2011,[14] he made his AFL debut in the 33-point win against Essendon at the Melbourne Cricket Ground in Round 11,[15] where he played primarily as a forward and recorded eight disposals, ten hitouts and two behinds.

[18] He returned to the senior side for the 76-point loss against Carlton at the Melbourne Cricket Ground in Round 20,[19] but he was dropped the next week[20] and managed just four matches in his debut season.

[28] He returned to the senior side for the three-point win against the Western Bulldogs at the Melbourne Cricket Ground in Round 14.

[31] He played his first AFL match for the year in the 17 point win against Richmond at the Melbourne Cricket Ground in round nine.

[62] Apart from his tapwork, Gawn's ability to kick goals and take contested marks drew the attention of the media with many predicting he would be the All-Australian ruckman after his form continued in the second half of the season.

[67] Fox Sports Australia journalist, Tom Morris, noted in August that Gawn had achieved his goal of becoming the best ruckman in the competition set the previous November.

[91] After Gawn's All-Australian year in 2016, external expectations on him were high, especially with the third-man ruck rule change—whereby only the two nominated ruckman were allowed to compete in the ruck—with Fox Footy personality and former player, David King, saying Gawn would relish in the rule change and "take his game to another level.

[95] In the opening round match against St Kilda at Etihad Stadium, Gawn recorded 49 hitouts and led Melbourne to the 30-point win, according to the Herald Sun's Lauren Wood.

[96] The Age journalist Rohan Connolly furthered this notion by saying Gawn's dominance over St Kilda ruckman Tom Hickey was crucial in the victory with his service leading to winning the clearance count.

[100] He ultimately missed ten weeks of football and returned directly to the AFL in the three-point win against West Coast at Domain Stadium in Round 14.

[102] In addition, his form was further affected when his ruck technique was scrutinised by the field umpires during the twenty-four-point win against St Kilda at the Melbourne Cricket Ground in round twenty-one, in which he was giving away several free kicks for which "[Gawn] had never given away in [his] life" and he consequently conceded ruck contests so he wouldn't give away free kicks.