Grady Louis McMurtry (1918–1985), a student of Aleister Crowley, was largely responsible for giving new life to the OTO, which he headed from 1971 until his death.

He studied engineering at Pasadena Junior College and met Jack Parsons at nearby CalTech through their mutual enthusiasm for science fiction. In 1941 he was initiated into the OTO. In 1942, as a member of R.O.T.C he was called to active duty amd took part in the Normandy invasion. He was recalled to active duty in the Korean War and retired as a Lieutenant Colonel.

Stationed in England in 1943-1944, he was a personal student of Crowley. Back in California after WWII, Crowley gave him a controversial letter that appointed him OTO representative for the United States, subject only to Karl Germer. When Crowley died in 1947, Germer became head of the OTO. McMurtry ended his involvement with the OTO in 1961 over disputes with Germer and moved to Washhington, DC.

Germer died in 1962 and in 1969 McMurtry returned to California to take charge of the OTO. By 1985, there were over 700 members in several countries. Since his death, the OTO has continued to grow to several thousand active members in over fifty countries.