2002–2006: Debut Seasons Montagna was recruited from the
Northern Knights in the
TAC Cup under-18s as the number-37 draft pick in round 2 of the
2001 AFL draft by St Kilda. He played his first game wearing number 28 for St Kilda in round 2 of the
2002 AFL season against the
Collingwood Football Club. Montagna played in St Kilda's
2004 Wizard Home Loans Cup–winning side. St Kilda defeated Adelaide, and on the way to the grand final. By this point, Montagna was establishing himself as a core part of the St Kilda team, setting a then club record for consecutive wins between round 1 and round 10 in the
2004 AFL season. Montagna did not play in the finals series, and St Kilda eventually fell six points short on the scoreboard in the Preliminary Final after qualifying for the finals series in third position. Montagna's 50th AFL match for St Kilda was in Round 21 of the
2006 AFL season, a 50-point win against the . 2006 was a breakthrough season. Consolidating himself in the senior team, he went on to play 22 games for the season, leading the club in inside-50s, running bounces, and was top-five in tackles and hard-ball gets. He averaged over 19 disposals per game.
2007–2011: Rise and Grand Final Losses In Round 8, 2007, in a match against Hawthorn, Montagna suffered a broken jaw but only missed one week with the injury. Although 2007 was the first since 2003 that St Kilda had missed out on playing in the finals series, it was the season that saw Montagna become a top-tier AFL footballer. Montagna played consistently throughout the season and continued the improvement he had shown in 2006. He played an accountable and hard-running role through St Kilda's midfield, averaging 24 disposals and 3 tackles per game and kicking 10 goals for the year. Some of Montagna's highlights for the year included best-on-ground performances against the Kangaroos, Richmond and Hawthorn in the second half of the year. Montagna was rewarded for his efforts with a third-place finish in St Kilda's 2007 best and fairest. Montagna played in St Kilda's
2008 NAB Cup–winning side—the club's third pre-season cup win. St Kilda defeated Richmond, and Essendon on the way to the grand final. 2008 saw Montagna continue to become vital in the St Kilda's midfield. St Kilda qualified fourth for the finals series and were defeated in the preliminary final by eventual premiers, Hawthorn. He finished the year with the most kicks in the competition and second for inside-50s. His season was rewarded by being selected for the first time to represent Australia against Ireland in the
International Rules series. Montagna's 100th game for St Kilda was in Round 2 of the
2009 AFL season against Adelaide at
AAMI Stadium, which St Kilda won by 32 points. He played in 21 of 22 matches in the
2009 home-and-away season, where St Kilda won the
minor premiership and qualified in first position for the finals series. A new club record of 19 consecutive wins between rounds 1 and 19 was set, the equal-third-best in league history. The club completed its best-ever home-and-away season with 20 wins and 2 losses. He played in the
2009 AFL Grand Final in which St Kilda lost by 12 points. Montagna averaged 27.9 disposals and 6.25 tackles in 2009 and was named in the
2009 All-Australian team for the first time. He finished second in St Kilda's best-and-fairest award (Trevor Barker Medal), was selected in the AFL's All-Australian team for the second year in a row, finished in the top 10 in the Brownlow medal, and capped off the year by representing Australia in the International Rules series for the second time. Leigh Montagna played his 150th game against Richmond in a draw in Round 2 of the
2011 AFL season at the
Melbourne Cricket Ground.
2012–2017: Club Rebuild and Retirement The departure of Ross Lyon at the end of the 2011 season resulted in the beginning of a complete rebuild for St Kilda; and, despite the retirements and movement of many of his senior teammates, Montagna remained a model of consistency and a key leader through the rebuild. He played 102 out of 110 games in that period, averaging 26.4 disposals and finishing fourth in the club best and fairest as well as representing Australia on two more occasions. 2016 saw Montagna play across half-back for the first time in his career; he excelled in that role, averaging 29.2 disposals per game and helped lead the club to within percentage points of playing finals for the first time since 2011. At the conclusion of the 2017 season, Montagna announced his retirement from the AFL. In February 2019, he was appointed as a Melbourne-based opposition analyst for
Fremantle Football Club. ==Commentary==