Kenny Slaughter, also known as Leatherface, is the inbred and intellectually disabled member of the Slaughter family who regularly murders and eats any perceived intruders in their rural home of Newt, Texas. 
In the first film, The Texas Chain Saw Massacre (1974), siblings, Sally and Franklin Hardesty go out with their friends to investigate their grandfathers grave robbing. They run afoul of Hitchhiker and eventually the rest of the Slaughter family and Leatherface kills off their friends and Franklin. Sally is kept alive and manages to make a run for it, with Leatherface and Hitchhiker in pursuit. Sally manages to get a passing truck to stop, running over Hitchhiker. While the panicking trucker and Sally escape, he throws a wrench at Leatherface, causing him to fall backwards and cut into his leg with his own chainsaw. Sally makes another run for it, and manages to escape Leatherface in a pickup truck.
After the events of the first film, Leatherface ran away to a town called Harlow and found an orphanage. The owner of the orphanage, Virginia "Ginny" McCumber, takes Leatherface under her wing. According to Fede Alvarez, the director of Texas Chainsaw Massacre, Leatherface might've been in and out of the orphanage to do things with his biological family every now and then, but he eventually settled down.
The Texas Chainsaw Massacre 2
In The Texas Chainsaw Massacre 2, Leatherface is referred to as "Bubba" and the family name has been changed to 'Sawyer'.
One night in 1987, Chop Top and Leatherface, now known as Bubba, go for a ride in his truck along with Nubbins' corpse. Bubba uses Nubbins as a puppet and attacks two young men in a car making a call to a radio station. The car crashes, the young men die and the Sawyer brothers get away.
Vanita "Stretch" Brock, a radio DJ, hears the screams, chainsaw and car crash and puts it on a tape. Later she brings it to Sheriff Lefty, the uncle to Sally and Franklin Hardesty, who decides to try and look for the killers.
Several nights after the first incident, Stretch is visited by Chop Top, who announces himself and Bubba to be big fans of her. When Stretch gives Chop Top a tour and they get to a dark room, Bubba runs out with his chainsaw and misses Stretch and accidently hits his brother in the head, ruining his wig. After getting yelled at by his brother, Bubba goes after Stretch. She runs into a room and repels Bubba by spraying him with a fire extinguisher. She closes a metal sliding door, which Bubba is unable to saw through. Just when she thought she was safe, Bubba broke into the room through the wall. He began sawing into a cooler full of ice and beer, but upon seeing her face to face, Bubba forms a crush on Stretch. He strokes her with his chainsaw and she compliments him, which Bubba seemingly couldn't handle it anymore and begins to saw into the shelves and the radio room. He does a dance and leaves, sparing Stretch.
He meets Chop Top, who just finished hitting L.G., Stretch's partner, in the head multiple times. Chop Top asks Bubba if he killed Stretch, to which Bubba lies and tells him yes. They take L.G.'s body, throw it in the back of Chop Top's truck and drive off. Stretch follows them to Texas Battle Land. She makes it there and Lefty arrives as well, but when they meet, she falls into a trap. Lefty enters the abandoned amusement park with three chainsaws with the plan of ending the Sawyers and saving Stretch.
Stretch falls into the butcher room and hears footsteps and hides as Bubba enters and is tasked by Drayton to take care of the meat. Bubba skins L.G. but stopped when he heard something, he grabbed a butcher knife and looked for the source of the noise, that was when he found Stretch hiding. Bubba panics, not wanting his family to find her, he places L.G.'s skinned face onto Stretch, disguising her as a dead body. He proceeds to dance with her, but upon hearing the destruction of his home caused by Lefty, Bubba ties Stretch up, tells her to stay and leaves the room. L.G., barely alive, gets up and helps Stretch escape, but soon dies after. Stretch then leaves the room.
Bubba is with his family, Chop Top is dancing with Nubbins' corpse while Drayton is worried about a cook-off. When Stretch runs by them, Drayton tasks Bubba with finding who just ran by. He does so and chases after Stretch, eventually cornering her. He held her in place with his chainsaw, not sure what to do next, when his brothers arrived, Chop Top telling Drayton that Stretch was supposed to be killed long ago. Chop Top begins chanting "Bubba's got a girlfriend!" repeatedly, making Bubba feel embarrassed. Bubba hits himself on the head with the shell of a lamp in frustration, Chop Top knocks Stretch out and the family go to the dining room.
Stretch wakes up, and after she does Bubba kisses her on the lips. The brothers fetches Grandpa and they have him whack Stretch with a sledgehammer, however, Lefty arrives and tells Stretch to leave. Bubba grabs his chainsaw and begins fighting Lefty. The sheriff impales Bubba with a chainsaw, going through his stomach. Bubba continues fighting but is knocked down by Grandpa when he threw a sledgehammer in an attempt to help him. Drayton, deciding to commit suicide, detonates a grenade he grabbed from Nubbins' jacket. The grenade explodes, blowing up the entire cave. Lefty is presumably the only casualty in this incident.
Leatherface: The Texas Chainsaw Massacre III
After the events of the second movie, Leatherface started living in a forest with his other brothers: Tex Sawyer, Tinker Sawyer and Alfredo Sawyer. He also lived with his mother, Anne Sawyer. His brother Alfredo owned the Last Chance gas station. Leatherface also had a daughter. Leatherface ends up fighting a survivalist named Benny, and he gets his head bashed in with a rock. Leatherface survives however.
Texas Chainsaw Massacre: The Next Generation
In Texas Chainsaw Massacre: The Next Generation, he was a cross dresser involved in an Illuminati conspiracy to provide society a source of horror. Leatherface, along with his brothers Vilmer and W.E. and Vilmer’s girlfriend Darla, hunt down lost people and murder them. Leatherface and his family do not eat their victims, however, rather they eat pizza.
Leatherface, like the original, is seen wearing an elderly lady’s face and wig. However, for the rest of the film he wears a black dress, a more feminine skin on his body, and a brown wig. When we first see him, he wears a camouflage jacket, his traditional yellow apron, and has a long brown curly wig.
Leatherface screams throughout the film. When he realizes that he’s been caught by Heather, he screams, along with Heather. When Heather temporary escapes from his hands into a storage room, he screams. After he throws her into a box and she keeps opening it, he continues to scream. It’s not until after he uses heavy objects to prevent her from escaping from the box that Leatherface has a total meltdown. He also screams after killing Barry. When he does so, it worries his brother W.E., who's outside and can only hear Leatherface screaming.
Leatherface appears to be the weakest the family and is hurt by the fighting that occurs. His brother W.E. abuses him relentlessly, to which Leatherface does not fight back but cries. During a fight between Vilmer, Darla, and W.E., Leatherface is seen cowering behind the refrigerator screaming, crying and plugging his ears.
During dinner, while dressed in a drag, Leatherface is seen doing his nails. At one point, Vilmer mentions how his brother (Leatherface) is tired of his current female face and wants a new one. He implies that Jenny’s face will be his new face, which Leatherface becomes excited over.
When Jenny escapes again after using Vilmer’s remote controls to mess with his bionic leg, Leatherface, in his full drag, chases Jenny with the chainsaw. During the chase, one of Rothman’s men, flying an airplane, kills Vilmer with the propeller, which Leatherface witnesses and appears to be devastated over it. When Jenny escapes in Rothman’s limo, Leatherface has a meltdown. He screams and emulates the infamous chainsaw dance seen in the original. After this he returns to Harlow.
Texas Chainsaw Massacre
In 2022, Leatherface is still living with Mrs. Mc in the now deserted town of Harlow when a group of young entrepreneurs arrive and attempt to gentrify the town, two members of the group, Melody and Dante, enter Harlow Orphanage. Melody tries to evict Mrs. Mc out of the home, to which she refuses as she still legally was allowed to live there, meanwhile Dante removes the confederate flag which had belonged to Mc's grandfather. Due to stress, Mrs. Mc starts to throw up and collapses, Leatherface comes and helps her up. Some officers arrive and they bring her to a paramedic truck, with Leatherface coming as well.
On the way to the hospital, Leatherface holds Mrs. Mc in his lap and is comforted by Mrs. Mc, being told that he is her boy. She suffers from a heart attack to which Leatherface panics, he puts her oxygen mask over her mouth and tries to save her, but to no prevail. Out of rage and agony, Leatherface kills the officer in the back of the truck by snapping his hand and stabbing him with the bone that was sticking out, he causes the dying officer to shoot the driver which leads to the truck crashing into a field. Leatherface exits the truck and skins Mrs. Mc's face and wears it as a mask, he props her corpse sitting up in the field. He finds Ruth, Dante's girlfriend, alive in the passenger seat and stabs her in the gut, he caresses her face before walking back to Harlow.
Leatherface goes back to the orphanage and finds Dante walking around the home, he cuts him across the face and leaves him to bleed out on the floor. Melody was there while this was happening and hid under Mrs. Mc's bed. After this Leatherface goes to Mrs. Mc's bedroom and breaks the wall open to retrieve his chainsaw he used from 1973. Before he is able to start it however, a mechanic named Richter enters the house while armed after having seen Dante walk out covered in blood. Leatherface attacks him and swings his hammer at Richter's leg, destroying it by bending it backwards, after this he stabs him in the head with a shard of broken glass on the window, causing him to fall to the ground and see Melody hiding under the bed. Leatherface grabs his sledgehammer and repeatedly bashes Richter in the head to the point of shattering his skull and tendering his flesh, all while Melody was hiding under the bed, having witnessed the brutal murder.
Leatherface leaves the room, but hears Melody sneaking around the house. He finds her at the bottom of the staircase and throws his sledgehammer at her, causing her to fall and break through the floor. She tries to crawl away but Leatherface listens to her and saws through the floor, she gets to a vent cover but gets covered in feces when the sewage pipe is sawed through. Melody's sister, Lila, finds her and gets her out, the two run to a party bus. Leatherface follows them to the bus and kills the bus driver, he enters the party room to which he is met with a group of young influencers, who begin to record him. Leatherface revs his chainsaw and begins to brutally murder every last one of the influencers. While he is going on his killing spree, Melody and Lila go into the restroom of the bus and escape through the ceiling window. Leatherface saws through the door but gets stabbed in the arm with a corkscrew.
As Leatherface is leaving the bus, Melody and Lila find a cop car and enter it, finding an elderly woman who turns out to actually be Sally Hardesty, the sole survivor to the original massacre from 1973. She tells the two girls to stay in the car while she confronts Leatherface, who is sitting in the orphanage alone. Leatherface is held at gunpoint and is asked by Sally if he remembers her, to which he doesn't. He walks out and finds the sisters hiding in the car, he grabs Melody but gets shot in the shot in the shoulder by Sally. The two start to fight with it ending with Leatherface impaling Sally with the chainsaw and tosses her onto some garbage bags.
Leatherface finds Melody and Lila in a garage, having crashed the cop car into it. He is about to kill Melody but is stopped by Lila when she aims a gun at him, but when it was found to be empty, he started chasing her. Lila falls to the ground and before he gets to saw her, Sally shoots Leatherface again, he stumbles away into an abandoned theater, Sally bleeds out to death. Lila enters the theater, armed with Sally's shotgun, but is attacked by Leatherface. The two have a scuffle, and when Leatherface is about to kill Lila, Melody returns and hits him in the chin with his own chainsaw, making him fall into a large body of water.
Several hours later, Leatherface reemerges and finds the sisters leaving Harlow in their car. He breaks the window and grabs Melody, decapitates her and holds her head up for Lila to see as the car drives away. Leatherface, while still holding Melody's severed head, swings his chainsaw around.
After slaughtering Melody and the rest of the visitors, Leatherface returns to the original farmhouse.