Creo was born in New York City, grew up in Hollis, took courses at the Art Students League, while working in advertising. Returning after World War II, Creo continued his art studies in New York. He summered in Gloucester where he painted with Emile Gruppe.

During the 1960’s and 1970’s, Creo’s work was sold at nearly two dozen one man shows in New York, Los Angeles, London and Rome, as well as in other galleries world wide. In 2004, the New Britain Museum of Art exhibited the Len Creo painting in its collection, which led to its acquiring 15 Creo paintings in 2006. Plans are under way to exhibit those recently acquired at the Bushnell Center in Hartford, Ct. Creo’s work is in the permanent collections of the Washington Museum of Fine Arts, New Britain Museum of American Art; Amherst College Museum, Georgia Museum of Fine Arts; Long Beach Museum of Fine Arts; Norfolk Art Museum; Syracuse University Museum;.Ulrich Museum; University of Maine; NYU, University of Wyoming Museum; Washington Museum Of Fine Arts.

His one-man exhibitions include ones at the Shayne Gallery, Montreal in 1981-82,1985,1989, and annually from 1991-2005, and 2007; seven at the Portal Gallery in London in the 1960s and 1970s, three at the Madden Gallery in Londonin the 1980s; ten at the Carter Gallery, Los Angeles from 1959-76; six at ACA Gallery in New York and three at the ACA Gallery in Rome during the 1960s & 1970s; five at the Chase Gallery, New York in the 1950s and 1960s, and three at the Galleria Margutta. His website lists additional one-man shows in Mexico City, Florence, Milan, Santa Barbara and England.