Eventually, it is revealed that Beckett is a true Renaissance Man, equally good at math and science and the arts.
Beckett tends to fall in love easily, yet be naive about women; his travelling companion Al Calavicci has playfully called him a "Boy Scout."
Beckett tries to do the right thing no matter what, although when the leaps hit close to home, he tends to lose perspective and make irrational decisions; at those times, he requires Al to guide him back to the right path.
Tom (Thomas Andrew Beckett) was a good athlete, an All-State basketball player, an Annapolis graduate, is a Navy SEAL Commander, and has a wife named Mary.
While at MIT, Sam and his mentor, Professor Sebastian LoNigro, developed a string theory of time travel ("Her Charm"; see below).
He speaks six modern languages including English, Spanish, French, Russian, German, and Japanese, but not Italian or Hebrew.
As a young adult in the 1980s, Sam was a key member of the Starbright Project (details on the nature of the project were not revealed on the show), where he would meet some of his closest and most trusted friends: Al Calavicci, a decorated naval officer; a brilliant computer programmer known simply as Gushie; and Dr. Donna Eleese, the love of Sam's life, whom he met in 1984.
In 1995, after constructing the necessary machinery, including a holographic imaging chamber and a supercomputer ("Ziggy") with access to vast historical databases, the project's funds were running thin.
Eager to prove his theories, Sam prematurely stepped into the nuclear accelerator chamber and propelled himself back in time.
As Sam would soon discover, quantum-leaping had an unforeseen side-effect: He was struck with partial amnesia; he describes his own situation with the analogy of his brain being like a hunk of Swiss cheese, with his memory full of holes and lacking some personal information about his past, the most consistently absent detail being his marriage to Donna (with Donna preferring that Sam not be reminded of their marriage so that he can more easily commit to the people his hosts are in love with and thus solve whatever he is there to accomplish, consoling herself about Sam's 'cheating' by reasoning that his amnesia means that he is not technically cheating on her but is the equivalent of a man unaware that someone else is in love with him).
When Sam corrected the timeline, he leapt forward, but not all the way home; this time, he found himself assuming the identity of a minor-league professional baseball player named Tim Fox.
Therefore, jumping from one part of the string to another would allow someone to travel back and forth within his own lifetime, thus making a "quantum leap" between each time period.
(How exactly these things are accomplished is never explained, but it has been suggested that this theory borrowed heavily from van Strickum's closed timelike curve.
This was also partly due to an "error" that was referenced and then corrected by Ziggy, implying that Sam would not be able to pull off a similar feat again and was once more limited to his own timeline.
This theory is later revealed to have been relayed to by the leaped Sam Beckett to an actor and would-be time traveller Moe Stein in "Future Boy" (whose original theory was simply connect the beginning and end of one's life) who explains the full version on his television show in response to a viewer question from young Sam Beckett who, at that time, was still a child living in Indiana; only his own lack of resources prevented Moe from creating Project Quantum Leap decades before Sam.