McAdoo designed a number of residential, civic, and commercial structures in the Seattle area in a modernist aesthetic influenced by the Northwest Regional style.

A residence designed by McAdoo in Burien was declared the "Home of the Year" by The Seattle Times in association with the American Institute of Architects.

In addition to his architectural work, he participated in the NAACP,[a] hosted a weekly radio show on racial issues for several years, and unsuccessfully ran for a seat in the Washington House of Representatives.

[1][2][4] In July 1942, following the United States' entry into World War II, McAdoo joined the Army Corps of Engineers at Camp Roberts, California, where he continued to work as a draftsman.

In October 1943, the couple relocated with their newborn daughter to Portland, Oregon, for McAdoo to pursue a job at the Kaiser Shipyards designing pipe systems for oil tankers.

He chose to enroll in UW, due to a more receptive response to his letters and his belief that Seattle would be a more racially tolerant environment for him and his family than Oregon.

While at UW, he published a junior project entitled "An Automobile Salesroom and Shop for Maintenance and Repair" in the university's architectural year book.

[1][2][5] While in college, he entered employment at a firm owned by James J. Chiarelli and Paul Hayden Kirk, prolific designers of Seattle homes who helped create the Northwest Regional style.

[1][10][11] McAdoo broke into real estate development in 1948, designing and establishing the nine-unit Ben-Mar Apartments, named for his children Benjamin and Marcia.

[4][7] McAdoo's early designs were strongly influenced by the emerging Northwest Regional style, alongside general modern architecture.

McAdoo and fellow architect Edward Watanabe designed the spacious residence in mid-century modern style, totaling 3,700 sq ft (340 m2) across a main floor and an exposed basement.

[11] After hosting a Ghanaian ambassador, McAdoo traveled to Ghana in 1960, seeking to set up an architectural business in the newly independent country.

That same year, he was appointed the Chief Housing Advisor of the United States Agency for International Development (USAID), and was sent to design modular homes in Jamaica.

[4][9][16] These homes were fashioned from concrete blocks and were able to be constructed by untrained builders, and allowed low-income areas to be connected to water and electrical infrastructure.

[9][10] In D.C., McAdoo designed elements of the John F. Kennedy Center for the Performing Arts supervised by chief architect Edward Durell Stone.

After a difficult housing search held back by redlining practices and seller's discrimination, they moved to the Hilltop Community in Bellevue, Washington, where they lived in a home designed by Paul Hayden Kirk.

[9][12] McAdoo continued his work with the General Services Administration at its Auburn offices, with his private architectural practice as a secondary job.

His projects during the late 1960s and 1970s include the Southcenter Blood Bank, the University of Washington Ethnic Cultural Center, and a warehouse complex at the Naval Submarine Base Bangor.

[18][19] Washington House of Representatives member Charles M. Stokes, a Republican, declined to run for reelection in order to pursue a State Senate office in 1954.

[4][20] Seeking to fill Stokes' now-vacant seat, McAdoo ran as a Democrat on a civil rights platform, advocating the elimination of sales taxes on food and clothing, greater funding for public schools, and support for the United Nations.

[4] The third place candidate, Paul Revelle, disputed the results; McAdoo had listed his office as his address for the election, but his Montlake residence was outside of the district.