But high school teachers are super-smart and can do just about anything:
https://en.wikipedia.org/wiki/The_Professor_(Gilligan%27s_Island)
Professor Roy Hinkley, Ph.D.
The Professor’s backstory identifies him as a high-school science teacher who was born in Cleveland, Ohio. His principal expertise was as a botanist, whose purpose in joining the ill-fated voyage that stranded the castaways was to write a book to be titled Fun With Ferns.
His main function on the show was to devise many ways for the castaways to live more comfortably on the island. Many of his inventions (including a method for recharging the batteries in the ubiquitous radio) used coconuts and bamboo, both of which were in plentiful supply.
Aside from his proficiency in science, he was also adept and well-versed in law, literature, social sciences, and the arts.
Besides a list of degrees from various schools (including USC, UCLA, SMU, and TCU) he provides in one episode, little was ever learned about his past and nothing was ever learned about his family.
In several episodes, brief remarks are made on his past: in the pilot he is described as a research scientist and “well-known scoutmaster”; in another when a big game hunter comes to the island and asks the Professor what sports he took, the answer is “chess”; after kissing Ginger for a prolonged period (during filming of a silent movie), he claims to be a “scuba diver” . . .
[Note: In the Ginger situation, I would have preferred applying my Scuba skills with Mary Ann Summers.]