William Howard Marcellus was born on February 24, 1907 to Irwin Paul Marcellus and Ida May Clark in Boise, Idaho. After graduating high school in Boise, he decided to study architectural engineering ay the University of Idaho. Marcellus was a member of the Atelier Idaho club, and as a freshman lived in Lindley Hall.

In 1927, he accepted a position as a draftsman for the State Department of Public Works (later the Idaho Transportation Department). During his time at the Department of Public works, he met Jeanne deRevere. They married in 1939. He was also a member of the Soil Conservation Committee, and worked to seed the 18 mile stretch between Pocatello and the Igo Railroad Overpass. This helped to prevent erosion and stop the spread of noxious weeds. Marcellus retired in 1972, and died one year later.

Marcellus left a lasting legacy of architectural design. Today, the Howard and Jeanne Marcellus House (located in Boise) showcases various architectual aesthetics. Some of which include the Cottage design as well as the Colonial Revival. Verne Wood, the second owner of the home, designed the second floor additional. This was completed in 1979.