In Round 8 of the
2011 AFL season, Breust made his debut against
St Kilda after performing well for Hawthorn's affiliate side in the
Victorian Football League,
Box Hill. He kicked 2 goals after coming on as a substitute. In Round 15 after a 2-goal, 16-possession game against
Collingwood, he was nominated for the
2011 AFL Rising Star Award. Breust improved more during the
2012 AFL season, particularly with his five-goal effort in Hawthorn's eight-goal win over Collingwood. He played predominantly as a forward, but had short bursts in the midfield throughout the year. Breust played in Hawthorn's losing Grand Final team. At the end of the year, he placed fourth in the
Peter Crimmins Medal behind winner
Sam Mitchell. In 2013, Breust kicked a goal in the last quarter of the AFL Grand Final against the
Fremantle Dockers to win his first AFL Premiership. In 2014, Breust began a streak of 29 consecutive goals without scoring a behind, tying with the record set by Tony Lockett in the 1995 season. The streak began during the last quarter of Round 5 against the Geelong Cats and was broken in Round 17 against the Adelaide Crows. In Round 21, 2017, Breust kicked his 300th career goal in a 27-point victory over
North Melbourne. Breust was widely regarded as having a below average
2017 season, kicking only 33 goals, his second-lowest annual tally to that date, just surpassing the 30 goals in his debut season. Breust enjoyed a return to form in the
2018 season, with him kicking 53 goals, being a member of the
All-Australian team for the second time, and finishing sixth in the
Peter Crimmins Medal tally. Breust had a below-average 2019. Without tall marking targets around them, his combination in the forward line with
Jack Gunston was seen as being rather ineffective, with the pair kicking just 60 goals between them, as opposed to 105 the previous season. On 18 February 2023, Breust was announced as co-vice captain of Hawthorn Football Club alongside fellow small forward
Dylan Moore to support newly announced captain
James Sicily. Breust kicked his 500th career goal in Round 12, 2023 against Port Adelaide. On 14 August 2025, Luke announced his retirement from the AFL at the end of the season after 14 seasons. ==Statistics==