 Lent used a wide range of techniques in his illustrations, including acrylic painting, cardboard cutouts, colored pencil and ink and wash.

Born in Boston, Lent attended the Boston Museum School where he graduated with a degree in art in 1953, after which he went to Italy and Switzerland on a study grant.He worked for the Container Corporation of America designing labels for cans and worked for the Bresnick Advertising Company where he designed bank advertisements.After receiving positive feedback from a juvenile-books editor at Atlantic Monthly Press, he put out "Pistachio", a story published in 1964 about a green cow and a circus that he wrote and illustrated.