The move comes as previous CEO Quentin Martin steps down as both CEO and a director voluntarily.
Rosander has a wealth of experience in the esports and betting arenas, previously working at several online gaming firms, as well as Electronic Arts (EA) Games.
Rosander said: "I am thrilled to be taking over as CEO and look forward to leading the company as we scale the business. We have a talented and experienced team here at Luckbox, and I am confident we can build on the excellent work done so far under Quentin's leadership to make Luckbox a world-leading esports betting destination."
Drew Green, Real Luck Group Chairman, said: "Thomas's past industry success and unique operational skill sets made him the optimal choice to become our CEO as we enter our next phase, execute the concise plan Thomas established as CCO of Luckbox and build a company culture that's focused on profitable growth.
"Thomas has a proven track record of scaling similar businesses to Luckbox profitably, and joined us having been CEO of Dunder Casino, which saw a compound monthly growth rate above 17% over two years. I would like to take this opportunity to wish Quentin all the best in his future endeavours."
Rosander will exclusively take part in the upcoming AffiliateCon Virtually Live show this Wednesday.