On 30 January 1945, Wurtsmith replaced Major General St. Clair Streett as commander of the Thirteenth Air Force. He was promoted to the rank of major general on 19 March 1945. The Thirteenth Air Force was tasked with the support of Lieutenant General Robert L. Eichelberger's Eighth United States Army in the Victor series of operations to clear the Southern Philippines that included the Invasion of Palawan, Battle of the Visayas, and the Battle of Mindanao. Operating under Air Vice Marshal William Bostock's RAAF Command, the Thirteenth Air Force also supported Lieutenant General Sir Leslie Morshead's Australian I Corps in the Oboe series of operations against Japanese forces in Borneo.