I can think of one historical figure who fit the bill. Michael Faraday, who established the basis for the concept of an EM field, had very little formal education. For such a person to rise to prominence in physics was as unthinkable in his day is it is now.
He was apprenticed to a local bookbinder and bookseller at age 14 and became a voracious reader as a teenager. He later wrote that one of the books he read during that time changed his life—Improvement of the Mind, by Isaac Watts. He rigorously applied the personal development principles within and began studying science on his own from the book shop.
He started attending public lectures of a prominent chemist, taking copious notes on lectures and sharing them with others. He gave the chemist he'd been following a 300 page book based on the lecture notes and the chemist later hired him as a secretary! He had to endure a multitude of slights in the company of other scientists due to having humble beginnings while they were almost universally gentlemen, but it was his ticket in. Once he was working as a prominent scientist's secretary, he had access to the scientists' professional circles, if not social circles. He relentlessly continued his studies and got so good that people could no longer ignore him. Within a couple of decades, he was awarded an honorary doctorate from Oxford and he eventually became the most prominent physicist in the world.
There are probably similar stories of slightly less prominent physicists in this century, I just haven't heard of them yet.