Harold Keeler, painter, printmaker, printer and teacher, was born in Denver, Colorado on October 9, 1905. He began his formal art training at the University of Colorado and the Chicago Art Institute from 1928 to 1931. After moving to Denver in 1932, he worked as a freelance lithographer in addition to making his own prints. In 1934, Keeler was employed by the Denver Art Museum as a print researcher and focused on Albrecht Durer's woodcuts. He was supervisor of the Colorado WPA Block Print Project between 1936 and 1937, during which time he printed several portfolios of multiple artists' works alongside fellow printmaker William Traher. From 1937 to 1940 he worked independently and taught at the Denver High School.

Keeler moved to Seattle, Washington in July of 1942 and was hired by the Boeing Company as an engineering artist and offset lithographer. He received a Ford Foundation Fellowship in 1961 at the Tamarind Lithographic Workshop in Los Angeles. At Tamarind he worked on several independent and collaborative projects, helping to establish the burgeoning workshop as a magnet for experimental lithography. After returning to Seattle in 1962, Keeler worked at the Burke Museum. He also printed Mark Tobey's lithograph Urban Renewal in 1963 for Tobey's original book, The World of The Market.

Keeler was a member of and exhibited with the Northwest Printmakers. His work was included in group exhibitions at the Art Institute of Chicago, 1932, 1934 and 1938; the Library of Congress, 1935; the Whitney Museum, 1942; the National Academy of Design, 1943; and the 1st National Print Annual held at the Brooklyn Museum, 1947. The work of Harold Keeler is represented in the collections of the Art Institute of Chicago, Illinois; the Denver Art Museum, Colorado; the Amon Carter Museum of American Art, Fort Worth, Texas; the Grunwald Center for the Graphic Arts, Hammer Museum, University of California, Los Angeles; the Philadelphia Museum of Art, Pennsylvania; and the Library of Congress, the National Gallery of Art and the Smithsonian American Art Museum, Washington, D.C.

Harold Emerson Keeler died in Seattle, Washington on June 7, 1968.