While a law student, Oaks served as an elders quorum leader in his ward in Chicago. After he returned to the Chicago Metro Area after being a clerk to Justice Warren, Oaks was a counselor in the ward Sunday School presidency starting in 1959. He also was a counselor in the presidency of the Chicago Stake genealogical organization. He was then called as a stake missionary and counselor in the stake mission presidency, a set of positions at the time that required him to spend about 40 hours a month proselytizing.