The 24-year old will return home to Ireland after 79 AFL games, originally getting drafted to the Bombers in late 2014 as a category B rookie.
His homesick issues have been well documented, with the speedster flying to Ireland during the pre-season to be with family.
McKenna said it was the ‘right time’ to hang up the boots but was grateful for the opportunity at Essendon.
“I do really feel the time is now right for me to return home to Ireland,” he told the club website
“I’ve made no secret of the fact that at some point, I’d want to be returning home to my family and I’ve been weighing up the decision recently. It’s been a difficult year for everyone, but it’s also been a chance to take stock and weigh up several things in my life, so the time is right.
“I will always be grateful for Essendon’s support of both myself and my family since I arrived at the club from the other side of the world at the end of 2014.
“I will miss my teammates and coaches and I want to thank the Bomber fans for their support across the journey too. I will always wish the boys well and hope they see success in the not too distant future.”
Bombers General manager of football Dan Richardson thanked McKenna for all his contributions to the club.
“We understand Conor’s decision to return home to be with his family and while we are disappointed to lose a player of his calibre from our list, he departs the club with our support to return to his homeland,” Richardson said.
“In recent years, we’ve had very open and honest conversations with Conor, and his desire to return back home to Ireland has been no secret.
“It has been a very trying year for Conor personally, too, but ultimately we accept that the pull to return home was too strong. We will continue to provide our full support to Conor as he embarks on the next phase of his life.
“We thank Conor for his contribution to the club and wish both he and his family all the very best for their future endeavours.”