Troast began his career in the 1920s, as a teacher at Sitka's Sheldon Jackson School.
Circa 1930, he left the school and established an architect's office in Sitka.
[2] Later that year he moved his office to Juneau, the largest city in the then-territory.
[3] Troast moved to New Jersey, and Manley opened his own Anchorage office in 1941.
In New Jersey, Troast lived in Clifton, and was associated with the family firm, the Mahoney-Troast Construction Company, headquartered in Passaic.