Part of the senior management team at Easter Road, McEwan also stepped into the role of interim chief executive for six months during the pandemic following the departure of Leeann Dempster in November 2020.
McEwan joined Hibs from the R&A in December 2019 as head of marketing and brand partnerships before being made commercial director in August 2021 following the arrival of Ben Kensell as CEO.
He worked to develop new income streams for the club, achieving year-on-year growth as well as securing a record-breaking retail deal, with a Hibs statement confirming he has left in order to take up a new challenge.
Kensell commented: “On behalf of the club, I would like to thank Greg for the big contribution he has made to Hibernian FC during his tenure.
“He has left the club in a strong position commercially, with a good platform that we can build on.
“He’ll always be a friend to this football club and I’m sure everyone wishes him the best of luck as he embarks upon his next challenge.”
McEwan added: “I have thoroughly enjoyed my time at Hibernian FC and have so many fantastic memories to cherish.
“I would like to take this opportunity to thank the Board, the supporters, businesses, and everyone else who has supported the club since I joined. We have achieved so much off the pitch and gone through so much over the last three years, and I look forward to seeing how the club progresses in the future.”