Known for his pin-up girl illustrations, Fritz Willis did a fifteen-year series of calendars for Brown & Bigelow including an "Artist's Sketchbook" pin-up series. He wrote and illustrated a children's book, Me Too, and wrote several instructional books: Art Shortcuts, Secrets to Still-life Painting, and Faces and Features.

His birth place is unknown. He attended the Vesper George Art School in California, worked in the film industry, and landed small roles as an actor. However art was his prime interest, and he did set designs for Warner Brothers. Then along with fellow worker Joe DeMers, they created a series of pin-ups for Esquire called "Esquire Gallery", a very popular series.

Willis went on to do illustration for Collier's, Redbook, The Saturday Evening Post and many advertisers including Pepsi Cola, Max Factor, Crown Zellerbach and covers for Ice Follies programs.

Source:
Walt Reed, The Illustrator in America

Fritz Willis, the final successor to Earl Mac Pherson in the Brown & Bigelow "Sketchbook" series, is perhaps the last major pin-up artist and the only one truly reflecting the sexual revolution. Primarily known for depicting brazenly sensual '60s women in semi-nude disarray, Willis has only a superficial similarity to Elvgren, the innocent girls next door of the latter having little to do with the wanton women of the former.

Oklahoma-born Willis had a distinguished career in magazine illustration. His clients included Collier's, Redbook, and the Saturday Evening Post, and his association with Esquire made him one of that magazine's earliest entries in its ultimately vain attempt to create a new Petty or Varga.

Source:
http://scandols.com/artists.htm