Skinhead was a member of Biff Tannen's gang and a supporting antagonist Back to the Future and its sequel Back to the Future Part II. Like the rest of Biff's gang, Skinhead earned his nickname from a characteristic trait, in this case, it was a crewcut.
Hey, Biff! Get a load of this guy's life preserver! Dork thinks he's gonna drown?
~ Skinhead makes a snide remark about Marty's "life preserver".
Skinhead, along with Biff and the rest of his gang confronted George McFly in Lou's Cafe. Biff asked George if he did his homework for him, and bullied him.
Biff noticed that Marty McFly (who had accidentally traveled back to 1955) was staring at him, and asked him "What're you lookin' at, butthead?". Skinhead then made a snide remark about Marty's down- vest, which he thought was a life preserver. This comment drew laughs from Biff, the rest of his gang, and even George. Biff then warned George never to set foot into the cafe, and Skinhead (along with Match and 3-D) followed Biff out of the cafe and the four boys jumped into Biff's 1946 Ford convertible, and drove off.
Several days later, Skinhead was seen at school, along with 3-D and Biff. In the cafeteria, they watched Biff, as he flirted with Lorraine Baines (Marty's mother), and were amused when Marty attempted to pick a fight with Biff. When Mr Strickland prevented the confrontation from happening, Skinhead and 3-D followed Biff out of the cafeteria, after Biff told Marty "Since you're new here, I'm gonna cut you a break. Today. Now, why don't you make like a tree... and get out of here?".
When Marty managed to knock out Biff at Lou's Cafe, he also knocked Skinhead, Match and 3-D to the floor before running out.
While Marty rode around the town square on a makeshift skateboard, Biff, Skinhead, 3-D and Match chased after him in Biff's car.
When Biff crashed his car into a manure truck, the car (along with Biff and his gang) were covered in manure. Skinhead's hair was also messed up, much to his fury.
Enchantment Under the Sea Dance
That's for messin' my hair!
~ Skinhead to Marty, as he, 3-D and Match lock Marty in the trunk of another car.
Skinhead was present at the Enchantment Under the Sea dance, along with Biff and the rest of his gang. Skinhead, Match and 3-D threw Marty in the trunk of another car, which Skinhead said was "for messin' my hair!" and slammed the trunk shut. Unfortunately for the bullies, the car belonged to Marvin Berry and the Starlighters (the band playing at the dance) and, when 3-D and Skinhead offended the band with racial slurs, the band chased the three boys away, and freed Marty.
Back to the Future Part II
Hey! Hey! You're coming with us upstairs!
~ Skinhead to Marty, in the altered timeline.
Skinhead appeared in the alternate timeline Biff created, where Skinhead, along with Match and 3-D, worked as one of Biff's bodyguards at Biff Tannen's Pleasure Paradise. He still had his crewcut, though his hair was now gray.
Back to 1955
(3-D, Match and Skinhead chase Marty into the gym) Where'd he go? He just came in here? (3-D notices the 'other' Marty on stage, and thinks it's the same person) (3-D: Look! How did he get upon stage?) I dunno, but when he gets down we're gonna nail him! (Match: How the hell he change his clothes so fast?) (3-D, Match and Skinhead run towards back-stage.)
~ Skinhead, Match and 3-D see Marty's 'past' self, and think that it's the same person.
When Marty returned to 1955 to repair the timeline. The younger Skinhead (along with Match and 3-D) caused trouble for Marty. At the Enchantment Under the Sea dance, Biff asked his gang where Calvin Klein (Marty's alter- ego in 1955) was, and Skinhead told Biff that "I don't know. I ain't his secretary!". Biff ordered his gang to find him, as Biff was seeking revenge against Marty for the 300 bucks damage to his car. Match, 3-D and Skinhead ran off to find Marty.
After Marty manages to retrieve the almanac from Biff at the dance, the bullies chase him through the school. Although Marty loses them in the gym, the bullies spot Marty's "other" self performing onstage at the dance. They assume it's the same person (though Match wonders how he changed his clothes so fast), and they prepare to get him when he gets off the stage. To save his other self (and to prevent a time paradox), Marty climbs up onto the rafters and drops three sandbags on them, knocking them out. It can be presumed that Skinhead, alongside Match and 3-D, regained consciousness shortly afterwards only to find out that Marty had already left.
Skinead is amused, when Marty attempts to pick a fight with Biff.
As the car turns a corner, Skinhead & Match throw bottles at Marty.
"S--t!"- Biff & his gang scream, before they crash into a manure truck.