He was a few doctors as well, and the assistant warden of a prison, and a surgeon in the Royal Canadian Navy, a schoolteacher, a college dean, and who knows what else. He is legendary for his ability to perform admirably whatever he was doing with whatever credentials he had assimilated. In any case, the torch has been taken up more recently by one Steven Jay Russell who has taken the legal system for a ride by impersonating a judge, a lawyer and a doctor to talk his way out of custody. His trademark is to escape on Friday the 13th. One Frank Abagnale made a jump for the big leagues by trying on the hats of a pediatrician, lawyer, university professor, stock broker, F.B.I. agent, airline pilot and motivational speaker.
Ordinary schmoes get into the impostor act when it's convenient and easy.
A web search gives me the case of Ron Weaver, who at age 30 was no longer qualified to play college football, but as the younger Ron McKelvey he was able to fulfill his pigskin dreams. Some poor schmuck created an email account in the name of Britain's Prince William to confuse a friend, and was soon flooded by fanmail. She was supported in her claims by members of the U.S Congress, as well as Hillary Clinton, Julia Roberts and Gloria Steinem. He flew volunteer medical missions to Mexico. And there's the impostor named Lewis Morgan who's been pretending for years to be Randy Meisner, the bass player for the Eagles, and has been using this ruse to scam folks along the way.