The news follows last week's announcement that Ron Dennis had been forced to relinquish his position as MTG chairman and CEO following a meeting of shareholders.
American businessman Brown - a familiar face in the F1 paddock thanks to high-profile sponsorship deals done by his company JMI - will work alongside COO Jonathan Neale, with both men reporting directly to the MTG board. McLaren said their search for a new CEO continues, but described Brown's arrival as 'part of a restructuring programme that will align the Group's commercial and strategic operations relating to achieving success in Formula 1'.
"I'm immensely proud to be joining McLaren Technology Group," Brown, 45, said. "I have the utmost respect and admiration for what the business has achieved to date, and I look forward to contributing to the next important phase in its development.
"Having worked closely with McLaren for many years, I've been struck by the talent and ambition of the entire workforce, and I very much look forward to complementing the business's many existing strengths, and building on them to drive future success in everything we do.
"As founder of Just Marketing International (JMI) - now the world's largest motorsport marketing agency - I've often worked closely with McLaren as I say, and I've developed some excellent relationships across the company. Together we've delivered some great sponsorship deals, including Johnnie Walker, GSK, Hilton, Lenovo, Chandon and NTT.
"Best of all, in my new role I'll be able to combine my absolute passion with my unparalleled area of expertise - respectively motorsport and marketing - while ensuring that the two stay totally aligned."