The Leeds-based giant became a unicorn, a term used to describe a billion-pound tech company, when it was acquired by the Canadian Stars group in 2018.
Last year, Mr Flint, the former CEO, was appointed as executive chairman of SBG.
A spokesman for Stars Group said: “As noted in this afternoon’s earnings call, we can confirm that Richard is indeed moving on.”
Mr Flint has been with SBG for 17 years and served as its chief executive officer from 2008 to 2018. Ian Proctor succeeded him as chief executive.
Mr Flint has more than 20 years’ experience in online businesses, starting as a Channel Director at FT.com and then as the Product Director of online start-up flutter.com, which merged with Betfair in 2001.
Prior to that, he worked as a consultant at McKinsey & Company from 1997 to 1999.