Boyle has been with the commission for just under four years, in a high-profile role as manager of investor education.
He was previously with ANZ, as its general manager of funds distribution, and Armstrong Jones.
"It's a good opportunity to get back into the investment side which is sort of my calling," he said.
He said Mint was growing quickly and there was work to do to increase the brand's reputation, its use of roboadvice and direct and adviser channels.
"It's a similar feel as in the old Armstrong Jones days. The investment style is something I really like and understand. It feels like the time is right for me."
He is leaving the commission on July 6 but has not set a start date at Mint yet.
His time at the commission had built valuable relationships with government and regulators, he said.
Meanwhile, Mint chief investment officer Paul Richardson is departing.
Chief executive Rebecca Thomas said his role with the fund manager had always been intended to be short-term.
He became involved in the investments of the business in 2013.
She said, if Richardson wanted to pursue more directorship roles in the investment arena, his position at Mint was a conflict.
