Born in what is today Croatia, he later became an American citizen.   After his demonstration of wireless communication through radio in 1894 and after being the victor in the "War of Currents", he was widely respected as one of the greatest electrical engineers in America. 

Much of his early work pioneered modern electrical engineering and many of his discoveries were of groundbreaking importance. During this period, in the United States, Tesla's fame rivaled that of any other inventor or scientist in history. Because of his eccentric personality and his seemingly unbelievable and sometimes bizarre claims about possible scientific and technological developments, Tesla was ultimately ostracized and regarded as a mad scientist.   Tesla never put much focus on his finances. It is said he died impoverished at the age of 86.

The International System of Units unit measuring magnetic field B (also referred to as the magnetic flux density and magnetic

induction), the tesla, was named in his honor.  as well as the Tesla effect of wireless energy transfer to wirelessly power electronic devices (which Tesla demonstrated on a low scale with incandescent light bulbs as early as 1893 and aspired to use for the intercontinental transmission of industrial power levels in his unfinished Wardenclyffe Tower project).

Aside from his work on electromagnetism and electromechanical engineering, Tesla contributed in varying degrees to the establishment of robotics, remote control, radar, and computer science, and to the expansion of ballistics, nuclear physics, and theoretical physics.

In 1943, the Supreme Court of the United States credited him as being the inventor of the radio.