A veteran of World War II, Mr. Tennant joined Leo Burnett in 1950 as its first full-time radio-TV writer and producer. He spent 20 years with Burnett, Chicago, eventually becoming worldwide creative director and chairman of Burnett's creative review committee.
He was the creative director on many of the early campaigns for Marlboro cigarettes, and in 1952 he created the "Tony the Tiger" character for Kellogg's Co.'s Frosted Flakes cereal.
Under Mr. Tennant's leadership, Burnett was responsible for famous taglines such as the Pillsbury song, "Nothin' says lovin' like somethin' from the oven," and United Airlines' signature theme, "Fly the Friendly Skies of United."
After resigning from Burnett in late 1970, Mr. Tennant became chief operating officer for Clinton E. Frank, Chicago. In 1973 he started his own shop, Don Tennant Advertising.
Fourteen years later, Springfield, Mo.-based Nobel Communications Co. acquired the agency to form Nobel-Tennant and later Noble & Associates. He was a consultant until the late 1990s, said his son Tim, who is president of the Los Agneles-based agency Aspect.
Mr. Tennant is survived by his children Tim, Andy, a TV and film director, and Tracy, a homemaker. In lieu of a memorial service Mr. Tennant requested his family host a large party celebrating his life.