Clemens grew up in Milwaukee and graduated in art history from the University of Wisconsin–Madison in 1932. He then studied fine art at the Art Institute of Chicago where he met his first wife Ruth a sculptor and fellow student who modelled for many of his more famous works. He began painting for the Depression-era Works Progress Administration and won several awards for figure painting, which he taught at Los Angeles’ Otis Art Institute in the early 1940s. Having settled in California he began an association with Life magazine, painting numerous portraits of the Film Stars of the day to accompany profiles in the magazine.

His sitters included Katherine Hepburn, Spencer Tracy, Audrey Hepburn, William Holden, Frank Sinatra, Henry Fonda, Ava Gardner and Frank Sinatra. The latter two, a married couple at the time became great friends of Clemens and his portrait of Sinatra, a birthday gift from Gardner became Sinatra’s favourite painting.

Clemens fame grew and in 1942 the Durand Ruel galleries mounted a solo show of his paintings, the first for an American artist since 1895. Through his work for Life magazine he met the actress Eleanor Parker who became his second wife (she went onto play ‘the Baroness’ in the Sound of Music). His work had the romantic ambiance, delicate hues and luminous quality of the 19th century French painters and critics often referred to Clemens as “the American Renoir”.

His work has been exhibited at the Carnegie International in Pittsburgh, the Metropolitan Museum in New York and the National Academy of Design where he was elected Academician in 1965. His ‘Head of Ruth’ is in the permanent collection of the Smithsonian.