Founder of the eponymous global ad agency that created the so-called Chicago School of advertising.
He worked on signs and advertisements for his father and then worked as a journalist before deciding to go into the more lucrative advertising career.
His style of advertising preferred striking, emotion-filled images over text-filled explanations. For example, he created the iconic images of the Pillsbury Doughboy and the Marlboro Man.
He was born in St. Johns, Michigan. His father was the owner of a dry goods store, and his father's ads for the store first inspired young Leo's creativity.
He and Charles Saatchi were two great advertising agency founders.