Ewanick, at GM for less than a year, currently holds the post of vice president of U.S. marketing, the Detroit Free Press reported Saturday.
He worked briefly at Nissan after serving as vice president of marketing at Hyundai Motor America.
GM Chief Executive Officer Dan Akerson said in a statement, "In a short time, with his marketing acumen and creative leadership, Joel has proven to be a vocal advocate for the consumer."
"He is the right leader to take GM's marketing strategy to the next level," Akerson said.
Ewanick will lead marketing for Buick, Cadillac, Chevrolet, GMC, Holden, Opel and Vauxhall brands, the newspaper said.