Demara's impersonations included a civil engineer, a sheriff's deputy, an assistant prison warden, a doctor of applied psychology, a hospital orderly, a lawyer, a child-care expert, a Benedictine monk, a Trappist monk, a naval surgeon,[2] an editor, a cancer researcher, and a teacher.

[citation needed] There are not many facts that have been proven about Demara, in spite of the articles, book, and big screen movie made about him during his lifetime.

[citation needed] He was apparently able to memorize necessary techniques from textbooks and worked on two cardinal rules: The burden of proof is on the accuser and When in danger, attack.

His father, Ferdinand Waldo Demara Sr., was born in Rhode Island and worked in Lawrence's old Theatre District as a motion picture operator.

During this financially troubled time, Demara Jr. ran away from home at age 16 to join the Trappist monks in Rhode Island.

The following year, Demara began his new life by borrowing the name of Anthony Ignolia, an army buddy, and going AWOL.

[6]: 80  He did not reach the position he wanted, faked his suicide and borrowed another name, Robert Linton French, and became a religion-oriented psychologist.

[5] After once more arguing with his superiors, this time over his lack of cooking skills, he left and moved to New Jersey where he joined the Paulist novitiate in Oak Ridge.

After his release he assumed a fake identity and studied law at night at Northeastern University, then joined the Brothers of Christian Instruction in Maine, a Roman Catholic order.

[4] That led to his most famous exploit, in which he masqueraded as Cyr, working as a ship's doctor aboard HMCS Cayuga, a Royal Canadian Navy destroyer, during the Korean War.

Accounts of his heroic efforts ended up in Canadian newspapers, reaching the mother of the real Joseph Cyr, who was quietly practicing medicine in Grand Falls, New Brunswick.

Faced with the embarrassment of having allowed an impostor into the Royal Canadian Navy's ranks, a board of enquiry instead chose to quietly dismiss him and force his deportation to the United States.

The MASH episode "Dear Dad... Again" included a one-time character Captain Adam Casey, likely inspired by Demara's exploits, who performs several surgeries, but turns out not to be a real surgeon.

According to his biographer, Demara's past became known and his position untenable when an inmate found a 1952 copy of Life with an article about the impostor.

When Demara's past exploits and infamy were discovered in the late 1970s, he was almost dismissed from the Good Samaritan Hospital of Orange County in Anaheim, California, where he worked as a visiting chaplain.

Demara died on June 7, 1982, at the age of 60 due to heart failure and complications from his diabetic condition, which had required both of his legs to be amputated.

[2] Demara's story was recounted in the 1960 book, The Great Impostor, written by Robert Crichton and published by Random House.

The book was a New York Times bestseller and adapted into a 1961 film by the same name starring Tony Curtis as Demara.