Finn first met Rey on the planet Jakku, after he rescued Poe Dameron from the First Order. When it appeared the latter had apparently died in his rescue attempt, their relationship at first got off on the wrong foot, when Rey believed he had to stole BB-8's master's jacket, only for him correct them regarding what actually happened. She assumed he was a member of the Resistance. However, he did not reveal that he was actually a former member of the First Order, as he was ashamed that he had been associated with them.
Over time, the two become good friends. When Finn finally revealed his true identity as a Stormtrooper to Rey, she was not angry with him for lying to her or about who he really was. After she was captured by Kylo Ren, he went to the Starkiller Base to rescue her, despite the fact that he did not know Rey for very long. When Rey is knocked out by Ren, he fights Ren to survive while trying to defend her, but he only ends up being seriously injured by Ren.
After waking up from his coma, Finn's first concern was Rey's whereabouts while she had journeyed to meet Luke Skywalker and convince him to help the Resistance. After learning that the First Order had managed to track the Resistance through lightspeed, Finn decided to leave and take a tracker in order to lead Rey away from the danger until he changed his mind and teamed up with Rose Tico to try to disable the tracker. Finn was reunited with Rey in the aftermath of the Battle of Crait, they shared a warm embrace, happy to finally see each other again.
Finn first met BB-8 after crashing on Jakku and recognized him as the droid who possessed the map to Luke Skywalker. Their first meeting did not go so well as BB-8 accused Finn of stealing his master's, Poe, jacket and electrocuted him until Finn cleared up the situation. After escaping from the First Order on Jakku, Finn strikes a deal with BB-8 that he'll get him to Resistance if he helps him get away from the First Order. Over the course of their adventure, they start to become good friends and Finn succeeds in reuniting BB-8 with Poe, which BB-8 is thankful for.
Finn first met Han Solo after he and Rey barely escaped from the First Order's military forces on the planet Jakku, he was amazed to learn that, Han fought with Rebel Alliance in Galactic Civil War, and is Luke Skywalker's old friend, over time, the two become good friends.
When Finn finally revealed his true identity as a Stormtrooper to Han, he was not angry with him for lying to him or about who he really was.
During their mission to rescue Rey and destroy the Starkiller Base, Finn witness Han being killed by Kylo Ren, and he is shocked by his friend's death. While Finn and Rey are trying to escape from Starkiller Base, Kylo Ren confronts them. Finn seems enraged with Ren, and tries to fight him to survive and to avenge Han's death, but he loses and is seriously injured by Ren.
Finn first met Chewbacca after he and Rey barely escaped from the First Order's military forces on the planet Jakku. During their escape from the Guavian Death Gang and Kanjiklub, Chewbacca was injured, when Finn was attending to his injuries, the latter repeatedly tried to strangle him six times, which Finn became annoyed by, so Chewbacca tried to strangle him the seventh time, after he complained about how the Wookiee almost killed him, but Finn ultimately forgave him.
Over time, the two become good friends.
Finn first met Rose Tico aboard the Raddus as he was making his way to the escape pods. When Rose saw Finn, she was excited, telling that she and her sister really admired his heroism in defecting the First Order and destroying Starkiller Base. However, upon seeing that he trying to get into an escape pod, Rose was disappointed with him. She decided to turn in him over for treason, but Finn tried to explain that he was trying to get his friend, Rey, to safety as he believed that the Resistance was doomed because the First Order was tracking them through lightspeed. Rose is shocked by this but still frustrated that Finn was trying to run away as her sister, Paige, recently died fighting the First Order.
Rose and Finn start to bond when they go on a mission to try to disable the tracker of the First Order, and at some point during their adventure, she developed romantic feelings for him. While they are in Canto Bight, Rose shows him how the people of the planet become rich by dealing arms to the First Order, including the use of child slavery and other immoral activities that cause more sufferings. Rose's ideals and experiences which later are contrasted with DJ's motto about being neutral and do not join sides, made Finn reflect about his own place in the war, leading him to eventually join definitely the Resistance's cause and stop running from his problems.
As a consequence of Finn's new resolve, when Finn confronts Phasma at the Finalizer, he tells her that he is in fact a "rebel scum". Later, at the Resistance battle against the First Order on Crait, he decides to sacrifice himself to destroy the First Order's Superlaser siege cannon, despite Poe and Rose pleading him not to. When Rose manages to save him by crashing her speeder into his, seriously injuring herself in the process, Finn is surprised. Rose confesses her feelings for him by saying that they are not going to win the war fighting what they hate, but saving what they love before kissing him and passing out. Finn carries Rose out of the battlefield and shows his care for her covering her unconscious body with a blanket while she is under medical treatment.
After this events, they remain being good friends. Finn invites her to go along in the mission to find the Sith wayfinder but Rose refuses because of other tasks she was assigned to, and Finn accepts her decision. During the Battle of Exegol against the Final Order fleet, Rose is reluctant to leave Finn when he and Jannah decide to stay behind to disable the transmitter of the Steadfast, only leaving after Finn and other Resistance members persuade her to. After the Resistance defeats the First Order, Finn sees Rose embracing Chewbacca, and looks happy to know that she managed to survive the battle.
Finn met Jannah when he and his friends arrived on Kef Bir to retrieve a Sith wayfinder in the ruins of the Death Star II, and Jannah agreed to help them retrieve it when the ocean tides were safe to travel. Later, as they fix the Millennium Falcon, Finn becomes surprised when Jannah reveals she used to be not only a member of the First Order but also a stormtrooper called "TZ-1719". Finn is overjoyed to meet another person with a similar background like himself as he never knew that there were other deserted stormtroopers.
Thus, the two begin to bond over their similar past and how they trusted their instincts to leave the First Order. Finn also tells her how he interprets this instinct as the Force and as fate that led him to defect and meet his friends, which arouses Jannah's curiosity, asking him if the Force is even real. Jannah listens to Finn carefully and shows interest everytime he mentions the Force, and she is the only person that Finn manages to talk about it (hinting at his newfound abilities) while he fails to express himself about the same to his friends.
Because of this initial interaction and how they could personally identify with the other, they soon became close and started to care for each other. After Rey went to the Death Star ruins alone, Jannah helps Finn to get there so he could aid Rey, but she immediately holds him back when they witness Rey and Kylo Ren dueling, not wanting him to risk himself trying to follow them.
Afterwards, they both return to Resistance base together, and Jannah decides to help him and the Resistance in the battle of Exegol. While they are working in turning off the navigation tower to stop the Final Order's fleet, Finn decides to stay behind to detroy the Steadfast that was rebooting the navigation tower, and Jannah willingly stays with him while the Resistance ground team evacuated. After accomplishing their goal, they hold on to each other for dear life as the ship comes crashing down and it seemes to be the end for them, but they are rescued by Lando Calrissian and Chewbacca. With the First Order defeated, Finn and Jannah celebrate the Resistance's triumph together.
- “That lightsaber... it belongs to me!"
"Come get it!”
- ―Kylo and Finn at Starkiller Base
Finn and Ren have been enemies ever since he captured Rey and killed Han Solo. He became enraged when Finn used Anakin Skywalker's lightsaber, stating that the weapon belonged to him. Finn mocks Ren telling him to come and get the saber, unaware that Ren is in fact Anakin's grandson, and the lightsaber does rightfully belongs to him. The two engaged in a lightsaber duel, as Finn was trying survive while denfending Rey that was unconscious, and trying to avenge Han's death. Although he was able to hold his own reasonably well for a relatively short period of time and even managed to lightly wound Ren's right shoulder, ultimately Finn was defeated by Ren, mainly because of the latter's superior experience and skills in lightsaber combat. Ren disarmed him of Anakin's lightsaber and dealt him a severe wound to his back.
- “You were always scum."
- ―Captain Phasma and Finn on the Supremacy
As a First Order stormtrooper, Finn was under the command of the leading stormtrooper, Captain Phasma. While under her service, Phasma regarded Finn as the best stormtrooper that the First Order ever had. After witnessing the death of a fellow comrade and realizing the First Order's cruelty, Finn was scolded by Phasma for removing his helmet when he had to take in the horrors he had seen on Jakku. It was at this moment that Finn decided to defect from the First Order; making him and Phasma bitter enemies. When Finn arrived on Starkiller Base with Han Solo and Chewbacca, they captured Phasma to deflect the shields surrounding the base. Finn mocked Phasma over having authority and threatened her to turn off the shields. Once Phasma turned off the base's shields, Finn had her thrown down the garbage chute on Solo's suggestion.
When sneaking aboard the Finalizer with Rose Tico to disable the lightspeed tracker so the Resistance could escape, they ended up being captured (due to them being betrayed by DJ) where Finn was coldly greeted by Phasma that orders their execution. After Finn and Rose were saved by Holdo's sacrifice, Finn was confronted by Phasma that was attempting to kill him, and they duel. Finn managed to gain the upper hand and as a defeated Phasma looked up at Finn, she tried to insult him stating that he was always scum. But as Finn at this point had decided to support the Resistance's cause, he proudly replied to her that he was "rebel scum" before watching as she fell to her death.