 In 1948, he won election to the Oregon State Senate, and served in that chamber during the 1949 session.Also in 1948, and again in 1952, William M. McAllister was a delegate from Oregon to the Republican National Convention, with his wife serving as an alternate in 1948.From 1948 to 1951 he was on the Oregon State Bar's board of governors, followed by the state bar examiners board from 1954 to 1956.