Norman Bates was the proprietor of the Bates Motel. After murdering his domineering mother, he developed a split personality based on her and began to commit murders under the "Mother" personality.
Following his father's departure when he was an infant, Bates was raised by his domineering and puritanical mother, Norma and they lived in a state of codependence. He eventually became interested in transvestitism – imitating his mother in the process – as well as the occult and metaphysics. At some point before he was nineteen, Bates tried to join the army, but was rejected.
When he was nineteen, his mother took a lover, Joe Considine. After Norman walked in on the couple having sex and Considine made plans to marry Norma, Norman became jealous. He poisoned them with strychnine and staged it as a murder-suicide, leaving a note in his mother's handwriting, claiming that Norma had killed herself and Considine due to a pregnancy and Considine's wife. Norman suffered a nervous breakdown and was institutionalized for some time.
To cope with the guilt of matricide, Norman's personality split into three facets – that of a son jealous of his mother, his mother, and a "normal" personality that concealed the existence of the other two. Whenever a "crisis" arose, Norman would drink until he blacked out, during which time he would dress up as his mother, whose personality would take full control.
In addition, Norman stole his mother's corpse and would maintain it, giving it a "new life."
Over twenty years later, in the middle of an argument between Norman and his "mother," a young woman named Mary Crane – signing in as Jane Wilson – arrived at the motel. Norman invited her to dinner, enraging his jealous mother, who then exclaimed, "I'll kill the bitch!"
During dinner, Mary – having overheard Norman's conversation with his "mother" – suggested to Norman that he institutionalize his mother, but he denied there being anything wrong with her.
Later, the "mother" personality took over and beheaded Mary with a butcher's knife as she showered. When Norman awoke from his "blackout," he heard the shower going in Mary's cabin. He looked through a peephole and spotted blood on the bathroom floor. Fearing Mary may have hurt herself, he went to investigate. He found Mary's corpse and believed his mother to be responsible. Norman dutifully cleaned up the scene and disposed of Mary and her belongings in a nearby swamp.
An investigator for Parity Mutual named Milton Arbogast later visited the hotel in search of Mary, who he claimed had stolen a car. Norman first lied saying he did not remember her at all but later claimed he did and had dinner with her. When Arbogast insinuated that they had more intimate relations and asked about his mother, Norman was upset and asked the investigator to leave. Arbogast complied, saying he would return with a warrant to speak to Norman's mother and revealed to him that Mary was wanted for stealing $40,000 rather than a car.
Not wishing to get the authorities involved, Norman allowed Arbogast to speak to his mother, on the condition that he go up to the house before Arbogast would be allowed to speak with her. Arbogast agreed to this condition and Norman went up to the house.
"Mother" got dressed and ambushed Arbogast, killing him with a razor.
Loomis spoke with Bates, who spoke of his mother's supposed death and his "reviving" her through "magic." He went on to state his suspicion that the two were not man and wife and that Lila had gone to the house while Sam spoke to him. Norman warned him of "Mother," causing Sam to worriedly go to Lila's rescue. However, before Sam could leave the motel, Norman incapacitated him with a whisky bottle.
As "Mother," Norman ambushed Lila in the fruit cellar as she stumbled upon his mother's corpse. As he charged at her, declaring himself as Norma Bates, Sam tackled and disarmed him.
Bates was confined at the State Hospital, where his mental condition was evaluated by Dr. Nicholas Steiner. The "Mother" personality completely took over his mind, believing that she had to, claiming that the "Norman" personality was, in fact, the murderous one.
- This section is missing information from Psycho: Sanitarium. Please contribute if you can!
Norman spent twenty years in an asylum, during which time he worked with psychiatrist Dr. Adam Claiborne. Despite Claiborne's efforts, Norman was not cured and escaped the asylum after strangling a visiting nun with her rosary beads and disguising himself as her.
He got in a van with another visiting nun and killed her with a tire iron before sexually assaulting her corpse. While driving away from the asylum, he spotted a hitchhiker, planning to kill him and use his body to fake his own death. Norman tried to kill him with a crowbar, but the hitchhiker managed to overpower him and kill Norman in self-defense. The hitchhiker burned the van and Norman's remains were unidentified for some time.
Subsequently, Claiborne began a murder spree beginning with Sam and Lila Loomis and ending with individuals involved with a film of Norman's life story. Much like Norman did with his mother, Claiborne had developed a murderous "Norman" personality.
Years later, the Bates Motel was turned into a tourist attraction, which included an animatronic Norman.
Norman was overweight and had thinning hair. He also wore a pair of rimless glasses.