The new deal will keep the 25-year-old in brown and gold until 2021.
“Securing Luke for a further four years is terrific news for the club,” Hawthorn recruiting and list manager Graham Wright said.
“He is a really important player for us and has played a crucial role in the forward line for the last six years.”
“To reach a deal with Luke before the season gets underway is really pleasing and we look forward to seeing him in the brown and gold for many years to come.”
Since making his debut in 2012, Breust has kicked 271 goals in 140 games for the Hawks, and is one of only four AFL players to kick at least 40 goals a season in each of the past five years, along with Lance Franklin, Tom Hawkins and Jack Riewoldt.