In 1951 he was the first black man to earn an architecture degree from the University of Oregon (UO).

Unthank worked on the courthouse in Lane County, Oregon; McKenzie Hall (formerly the UO School of Law building); and Kennedy Junior Middle School in Eugene, Oregon.

Following Unthank's graduation from the School of Architecture, he and Burgess married on July 7, 1951, in the state of Washington, because interracial marriage was illegal in Oregon.

[9] In 1980, following twenty individual AIA awards, he was named a Fellow of the American Institute of Architects, "recognizing his design work on the Lane County Courthouse, the former UO Law School, Central Oregon Community College campus buildings in Bend, the U.S. Consulate Quarters in Fukuoka, Japan, and numerous banks, professional offices, churches, and private residences around the state of Oregon".

The building had previously been named after the Ku Klux Klan leader Frederic Stanley Dunn.

[10] In May 2021, the University of Oregon Board of Trustees, at the recommendation of UO President Michael Schill, approved a transfer of the name Unthank Hall to the new dormitory building set to open in August 2021.