George McFly is a major character in Back to the Future, a secondary character in its sequel and a minor character in Back to the Future: Part III. He was portrayed by Crispin Glover in the 1955 and 1985 versions. For the 2015 version and Back to the Future: Part III, he is portrayed by Jeffrey Weissman.
George is Lorraine Baines' husband and Marty, Linda and Dave's father. In the original timeline, he is Biff Tannen's employee. When the history was rewritten, he became Biff's boss instead of him. We also know that he loves science-fiction by writing his own stories and watching TV programs on it.
In 1955, he is a shy and nerdy student constantly bullied by his entourage. Until 1985, he never changed and was dominated by Biff, his supervisor and old school bully. However, when Marty went back in 1955, he learned to George how to be brave and this experience has paid off: he managed to stand up to Biff by punching him in the face and taking Lorraine to the ball. In the rewritten 1985, he became a big and rich author respectable and respectful.
Back to the Future
He is seen for the first time in his house at Hill Valley. Biff who had borrowed his car, argues with him and refuses to pay the damage he caused. He is humiliated in front of Marty by his boss before this one leaves. During the evening, he watches TV with his other son Dave and stupidly laughing at it. Lorraine seems to regret her wedding with him.
His original version of 1985 is no longer seen and the next time George appears is when Marty goes back in 1955. The latter enters in Lou's Cafe, meets his father and Biff both as teens. Marty is shocked by seeing him and George leaves the cafe in bike. Then, we see him watching Lorraine in her house with binoculars in a tree. Marty is dumbfounded again by that behavior. George suddenly falls on the road and a car is about to crush him. Marty runs to his father and receives the impact for him. This one doesn't understand what's happening and flee with his bike.
On his side, Marty learns with Doc that he changed the history with the car accident: George was supposed to be hurt and then meet Lorraine but everything was reversed because of Marty's intervention. He is now forced to make his parents meet each other. He tries it in high school but fails when he understands his own mother had a crush on him. He then decides to make them fall in love at the "Enchantment Under the Sea" ball.
He talks to his father again in the high school refectory and learns about his first si-fi stories. When Marty pretend to him Lorraine loves him and wants him to invite her for the ball, he is very hesitating and panicked. Plus, he is held back by Biff. He is also worried Marty always following him everywhere. He finally decides to not invite Lorraine and says nobody will force make him to. During the night, Marty comes in his house, disguised as Darth Vader and threats him to melt his brain if he don't invite Lorraine for the ball. Terrified, George executes.
Tomorrow morning, he begs help to Marty. As he enters to Lou's Cafe, he tries in vain to talk to Lorraine. Biff then interrupts him and Marty steps in. He defeats Biff and his gang during a skateboard/car chase and George fails again.
The same day, Marty and George rehearse their scene for the ball: Marty will wait with Lorraine in a car at the parking lot. He will pretend to harass Lorraine and George will intervene to hit Marty before leaving with Lorraine. George is still nervous and Marty wants him to trust him because as he says: "if you put your mind to it, you can accomplish anything". The night, we see him dancing alone at the ball waiting for his moment. Later, he is looking at his watch and he has to go. He only arrives in front of the car when Biff has replaced Marty and he harasses Lorraine himself.
George then panics when he sees the bully, but orders him to leave Lorraine alone. Biff gets out of the car, tries to break George's arm but the latter clenches his fist and hits him violently in the face. Having confidence in him for the first time, he reaches out to Lorraine and takes her with him to dance. Marvin, one of the Starlight singers, injured, is replaced by Marty on guitar for the concert. George rejects a last bully named Dixon before kissing Lorraine.
He greets Marty with his hand, who greets him in return and dances with Lorraine on the song "Johnny B. Goode" played by Marty himself. At the end of the ball, George and Lorraine go to see Marty and George thanks him for his advice and together, say goodbye to Marty.
Everything having returned to normal even better than expected, Marty was sent back in 1985. The next day, he noticed everything changed at home: his family, living conditions, the relationship between Biff and George who now has the upper hand over his former bully. As the timeline changed, George did too: he became a big sci-fi author who released his first novel "A Match Made in Space". When Marty goes out with his girlfriend Jennifer, and discovers that his parents bought the 4x4 he wanted, the latter observe him, smiling and happy.
Back to the Future: Part II
George is appears as a secondary character in the sequel. He is quickly seen at the beginning of the film before Doc takes Marty and Jennifer in 2015. The three go the futurist Hill Valley and Doc puts Jennifer asleep to not making her know too much about the future. However, she is taken by two cops to her new house in "Hilldale".
When she wakes up, she hides herself in a closet and sees Lorraine and George as elderly persons. The latter hurted himself by playing golf and is hanged upside down by an "Ortho-lev". Then, Jennifer passes out when she meets her 2015 other self and is taken again by Doc and Marty to the DeLorean. During this time, an old Biff Tannen stole the car to go back in 1955 to give the Almanac to his other self.
When Marty and Doc went back to 1985, they realized Biff took over Hill Valley. Tannen is also married to Lorraine and George is totally missing. Marty finds out in a newspaper he died and learns Biff killed him. To modify this timeline, Doc and Marty have to go back in 1955, when Biff got the Almanac.
At the end of the film, Marty got back the Almanac and burns it. He looks at the newspaper he kept and the title about his father changed from "George McFly murdered" to "George McFly honored" implying he is alive.
Back to the Future: Part III
George is now a minor character only appearing at the end of the film where he asks to Lorraine where his glasses are.