The rocker, awarded his qualification Thursday by London's Imperial College, said submitting his thesis, "Radial Velocities in the Zodiacal Dust Cloud," to supervisors was as nerve-racking as any stadium gig.
"I'm feeling rather joyful. I cannot tell you how much of a weight off the mind it is," May said late Thursday.
May was an astrophysics student at Imperial College when he joined Freddie Mercury and Roger Taylor to form Queen in 1970, but dropped his doctorate as the glam rock band became successful. Queen was one of Britain's biggest music groups in the 1970s, with hits including "Bohemian Rhapsody" and "We Will Rock You."
Following Mercury's 1991 death, May produced two solo albums. The latest, "Another World," appeared in 1998.
But the guitarist continued to pursue his interest in astronomy and last year co-authored a book on the subject, "Bang! The Complete History of the Universe."
He told reporters Thursday that handing over his completed thesis and facing examiners for a review of his work had been a new challenge.
"It was a bit nerve-racking walking into the room but once we got going it was fascinating," May said. "There's always that feeling they could ask that big question that could sink you but luckily they didn't."
May will be formally presented with his doctorate next May at a ceremony at London's Royal Albert Hall.