Nagel was born in Dayton, Ohio. However, he was raised and spent most of his life in the Los Angeles area. He attended the Choinard Art Institute in Los Angeles.

In his lifetime he created hundreds of illustrations on board, paper, and canvas, most of which emphasizes the simple grace of and beauty of the female form.

Nagel’s work is superficially reminiscent of Japanese woodblock prints, with their unusual cropping and large fields of color, but thematically, Nagel’s shares more in common with 1920s Art Deco and the design aesthetics of J. C. Leyendecker or Maxfield Parrish.

Nagel would start with a photograph and work down, always simplifying and removing elements which he felt were unnecessary. The resulting image would look flat, but emphasized those elements which he felt were most important.

Nagel’s figures generally have black hair, bright white skin, full-lipped mouths, and the distinctive Nagel eyes, which are often squared off in the later works. Because of the intense stylization and reduction of facial features into clean lines, generally the figures resemble each other, though Nagel worked with many models, including Playboy Playmates Cathy St. George, Tracy Vaccarro and Shannon Tweed. Nagel also painted several celebrity portraits including those of Joan Collins (whose portrait was subsequently released as a limited edition print) and Joanna Cassidy.

While Nagel’s work is mostly represented by aloof, if also seductive women, they are rarely, if ever, presented in a submissive relationship with men. These are highly sexual, but empowered and intelligent, women. Nagel also painted men, though only one was ever released as a fine art print while Nagel was alive. He had and continues to have a devoted following of collectors.

Through work connected with Playboy and the pop group Duran Duran, for which he designed the cover of the best selling album Rio, as well as many commercial projects, including work for Intel, Lucky Strike cigarettes, and Budweiser, Nagel and his work garnered international acclaim.

In 1984, at the age of 38, the artist participated in a 15-minute celebrity “Aerobathon” to raise funds for the American Heart Association. Afterwards, he was found dead in his car, and doctors determined by autopsy that he had suffered a heart attack.