Little of the Burglar's early history is known, but it is mentioned that even in his younger years he was a criminal.
At some point in his life, the Burglar was caught and send to prison. The Burglar became the cellmate of the infamous depression era gangster "Dutch" Mallone. In the 1930's, Mallone lived in New York City's Forest Hills section in the very same house that was now inhabited by Ben Parker and his family. It was long rumored that Mallone had hidden millions of dollars away somewhere. However, now Dutch Mallone was an elderly man. One night, the Burglar overheard Dutch Mallone talking in his sleep about where he hid the money. The Burglar heard that it was somewhere in his old house in Forest Hills. (To learn about Uncle Ben, click on his highlighted name above.)
Later, now out of prison, the Burglar heads to a Manahattan television station to find the location of Mallone's old home. At the station, the Burglar robs it and finds out the information he needs. Fleeing the scene, he is chased by office security and runs into a young Peter Parker (who was still dressed as Spider-Man). The officer yelled to Peter to trip the crook up before he could get to the elevator. However, Spider-Man refused to help, allowing the Burglar to make it into the elevator and escape. (Click on the highlighted name above to learn more about Spider-Man.)
One night, a few weeks, the Burglar broke into the Parker home to search for the money (unknown to the Burglar, however, the money was hidden in a box behind a wall in the House, but had long ago been devoured by silverfish). Peter was away making a personal appearance as Spider-Man during this time and he wasn't home. But, the Burglar took Ben and May Parker by surprise and held them at gunpoint. He then grabbed May and demanded she show him around so he could find something. Furious, Ben ordered the Burglar to unhand May and angrily reached toward him. Frightened, the Burglar shot Ben and ran out of the house. Ben Parker died. (To learn about Aunt May, click on her highlighted name above.)
While he was fleeing the scene, the Burglar began to be chased by police. Eventually, he runs into a warehouse. It was here that he runs into Spider-Man--wanting to avenge the death of his Uncle Ben. Spider-Man attacks and knocks the Burglar out. It is at this moment that Spider-Man realizes that the man is the thief he had encountered before at the television station. Spider-Man left the Burglar there to be captured by the authorities.
Years later, having served his time in prison, the Burglar is released (despite being deemed mentally unstable by psychiatrists). Still wanting to find Mallone's hidden treasure, the Burglar rents the old Parker home. After tearing it apart and finding nothing, he decided to interrogate Aunt May, who now resided in the Restwell Nursing Home on Long Island. Once arriving to the nursing home, the Burglar held prisoner the the nursing home's owner, Doctor Ludwig Rinehart. He pressured Rinehart to let him take May Parker. (Rinehart was actually the villain Mysterio in disguise). Rinehart decided to play the Burglar and allow him to talk to May Parker--he figured he could dispose of the Burglar once he learned of the treasure's location. So, he faked Aunt May's death from a heart attack to allow the Burglar to take her from the nursing home without Peter knowing. (Click on the highlighted name above to learn more about Mysterio.)
Soon, the two's "partnership" sours and the two criminals turn on each other--Mysterio wanting the money for himself. Rinehart revealed his true nature before beating and imprisoning the Burglar. However, the Burglar was able to escape from Mysterio. The Burglar ran to the same warehouse he was first captured by Spider-Man—he was holding May Parker captive there. However, Spider-Man tracked him down and and confronted the Burglar there. It was then, that Spider-Man revealed his true identity as Ben Parker's nephew. Believing that Spider-Man was about to kill him as revenge for murdering his Uncle Ben, the Burglar suffered a fear-induced heart attack and died. Among his last words was the request to Spider-Man to apologize to the family of an old man he had murdered on his behalf.
More recently, it was revealed that the Burglar had a daughter. After going from foster home to foster home the daughter turned up as Jessica Carradine, a photographer for the Daily Bugle. (To learn about the Daily Bugle, click on the highlighted name above.)
In Spider-Man and Spider-Man 3, the Burglar's character is a carjacker rather than a burglar. In the movie though, the thief ends up shooting and killing Uncle Ben while Peter's uncle was waiting for him outside of a library.