A proposed Gambling Commission licence condition would stop Great Britain operators offering third-party bets on the National Lottery game.
The consumer protection specialist will start a five-year term on 30 September after a long interim period at the regulator.
The DCMS appointment brings a new minister to affordability checks, a live issue for racing and betting groups.
The appointment follows a day of uncertainty over whether Baroness Twycross would keep the brief, while Lisa Nandy remains in charge of the department.
The shift ends the presumption that penalty-like payments would go to GambleAware, after the charity’s closure and the levy’s arrival.
Most licence categories will go up from October, but society lotteries are frozen and some on-course bookmakers will move to a gross-gambling-yield model.
Ministers say geo-blocking and VPNs have left a loophole that keeps offshore brands visible in British sport.
Ministers are moving after delays, pressure from industry and Everton’s Stake deal.