He was responsible for creating some of advertising's most well-known characters and campaigns of the 20th century, including Tony the Tiger, the Marlboro Man, the Maytag Repairman, United's "Fly the Friendly Skies", and Allstate's "Good Hands", and for garnering relationships with multinational clients such as McDonald's, Hallmark and Coca-Cola.

A few employees at Cadillac formed the LaFayette Motors Company – triggering Burnett to move to Indianapolis to work for the new firm.

[13] After spending a decade at McKee's, and working through the stock market crash of 1929, Burnett left the company.

[citation needed] In December 1967, nearing the end of his career, Burnett delivered his "When To Take My Name Off The Door" speech at the agency's holiday gathering.

[15][17] On June 7, 1971, Burnett went to his agency, pledging to colleagues to work three days per week due to health problems.

[20][21] Now a part of Publicis Groupe, Leo Burnett is one of the largest agency networks with 85 offices in 69 countries and 9,000+ employees.

[28] Burnett believed in finding the "inherent drama" of products and presenting it in advertising through warmth, shared emotions and experiences.

This is evident on such campaigns as Jolly Green Giant, Pillsbury Doughboy, Tony the Tiger and more famously the Marlboro Man.