Breust fractured his left tibia during 2008, but after recovering from that injury he received an invitation to trial with the Hawks and was then selected in the draft.

[3] 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.

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.

[6] 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.

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.