Pentti Rinta joined Marimekko as a fashion designer in 1969. He remained with the company until 1987, during which time he designed some of Marimekko's bold and colorful prints.

In the 1970s, Penti's Marimekko designs appeared in Vogue and magazines around the world. In 1972, he designed the now-classic and popular corduroy men's suit, Kuski (Driver). Among Penti's most famous Marimekko prints are Kirjo (Spectrum) and Haamuruutu (Phantom Square).