Dunstan, 28, began his days at Moorabbin after being drafted with a second-round pick out of South Australia.
Hard at the ball, but not always the tidiest user, Dunstan would wear the Saints' red, white and black guernsey on 116 occasions before running out as a Demon for five games across the past pair of seasons.
Announcing his time at AFL level was up on Tuesday, Dunstan wished to thank both clubs for taking a chance on him, tipping his cap to the people he met along the way.
“I would just like to thank St Kilda Football Club for the opportunity, as well as Melbourne. I've thoroughly enjoyed my time at the club and feel lucky to have been a part of such a great culture,” Dunstan told Demons Media.
“I've met some amazing people over the journey and some lifelong friends. Thank you to everyone that has helped me along the way, I'm looking forward to the next chapter.”
As the person who drafted Dunstan in 2013, Melbourne's GM of Football Performance Alan Richardson has seen every iteration of the midfielder's career, adding that Dunstan's strength of character was second to none.
“Luke's commitment to the team is a testament to his character. His resilience over the journey has been incredible and he has shown what it truly means to give your all for the team,” Richardson said.
“We wish Luke the very best in all his future endeavours, knowing that whatever path he chooses, he will approach it with the same dedication and passion that defined his significant AFL journey.”
Melbourne has further list decisions to make following Dunstan's retirement, with each of Andy Moniz-Wakefield, Kye Turner, James Jordon and the injured Jake Melksham all uncontracted for the 2024 season.