William O. Wooldridge is an American soldier who served on active duty in the United States Army from 1940 to 1972. He was picked by General Harold K. Johnson to be the first Sergeant Major of the Army.

Sergeant Major Wooldridge was born in Oklahoma and joined the Army shortly before the outbreak of World War II. He served the early part of the war with British forces in Iceland. Wooldridge was later decorated for gallantry during the Battle of the Bulge. He was awarded a Silver Star and a Purple Heart.