The Phantom Menace
Thirty-two years before A New Hope, Obi-Wan is a young Jedi Padawan. In the beginning of the film, Qui-Gon Jinn takes Obi-Wan with him to negotiate with the Trade Federation who are closing off the planet of Naboo. Unfortunately, they are attacked by battle droids when they arrive on the flagship. The two Jedi retreat and land on the planet where they meet Jar Jar Binks. The Gungan helps the Jedi meet up with Queen Amidala.
When the two land on Tatooine later on, Obi-Wan meets the young Anakin Skywalker. Even though Obi-Wan's master believes that Anakin has great potential and is "The Chosen One", Obi-Wan disagrees and convinces the Jedi Council to forbid the training for he is too old and has far too many emotional attachments at home.
At the end of film, a final battle ensues between Darth Maul and the two Jedi. After a lengthy lightsaber battle, Darth Maul stabs Qui-Gon Jinn. Obi-Wan, now filled with rage, fights more aggressively and manages to slice Maul in half. Qui-Gon Jinn dies in his arms, but not before asking Obi-Wan to train Anakin to become a Jedi. Obi-Wan promises to do so and is promoted to the rank of Jedi Knight.
Attack of the Clones
Ten years after the events of The Phantom Menace, Anakin has grown to be a Jedi Padawan but is beginning to show some signs of ruthlessness. He believes that Obi-Wan is holding him back from his true potential.
Obi-Wan sets out for the planet Kamino during his mission to find the person responsible for the assassination attempts on Queen Amidala. While on Kamino he learns about the clone army being built for the Galactic Republic, and later encounters Jango Fett who is behind the assassination attempts, as well as his son Boba. After an unsuccessful attempt to capture Jango Fett, Obi-Wan plants a tracking beacon on the ship.
While on the planet Geonosis, Obi-Wan learns about the Separatists/Confederacy of Independent Systems and how they are trying to pull away from the Republic. After sending a message to Anakin, Obi-Wan is apprehended. Anakin and Padme Amidala travel to Geonosis to rescue Obi-Wan but are unfortunately captured themselves. The three of them are sentenced to death in front of a crowd but are spared when Mace Windu and Yoda show up with hundreds of reinforcements. A lightsaber battle ensues between Anakin, Obi-Wan, and the former Jedi Count Dooku who is in charge of the renegades. During the fight, Anakin gets his right arm cut off. The two of them, later assisted by Yoda, are unable to defeat Dooku as he escapes from the fight.
Revenge of the Sith
Three years after the events of Attack of the Clones, Obi-Wan is now an esteemed Jedi Master and Anakin is a Jedi Knight. On a mission to rescue the kidnapped Supreme Chancellor Palpatine, the duo once again encounters Count Dooku. After another lightsaber battle, Anakin slices off Dooku's hands after Obi-Wan is knocked unconscious. Anakin then violates Jedi Code by killing Dooku in cold blood, an act he was encouraged to do by Palpatine.
Obi-Wan is then sent on a mission to Utapau to deal with General Grievous. When he arrives at the Separatist encampment, Grievous engages in battle with him. Obi-Wan is nearly defeated by kills the general with a blaster. Unfortunately, things take a turn for worse when Palpatine issues Order 66 to the clones, causing all of the clones to turn against the Jedi. Obi-Wan barely escapes with his life and meets up with Yoda and Senator Bail Organa. The three of them return to the planet Coruscant, the home of the Jedi Council. They are horrified when they discover that all of the Jedi there have been massacred, including the children in training. Even more horrifying is the revelation that Anakin is the killer. Obi-Wan doesn't want to have to kill his best friend but reluctantly accepts the fact that he's gone to the dark side.
Before heading off to fight Anakin, Obi-Wan goes to Padme, Anakin's wife, and informs her of her husband's activities. She refuses to believe Obi-Wan and instead heads to Mustafar to confront Anakin herself. Obi-Wan hides on her ship, knowing that he must deal with Anakin no matter what. When Padme confronts Anakin, she is shocked to learn that Obi-Wan was telling the truth. Obi-Wan emerges from the ship, causing Anakin to believe that Padme betrayed him. He chokes Padme into unconsciousness. After drawing lightsabers, Obi-Wan and Anakin engage in an epic lightsaber duel that eventually ends when Obi-Wan severs Anakin's legs and one arm in a single attack. He takes Anakin's lightsaber and leaves him to burn in the lava. However, Palpatine arrives shortly after Obi-Wan leaves and rebuilds Anakin into Darth Vader.
Padme gives birth to Anakin's two children, Luke and Leia, and passes away. Luke is given to Anakin's stepbrother and Leia is given to Bail Organa.
A New Hope
A New Hope was Obi-Wan's first appearance in Star Wars (since it was the first Star Wars movie released), but it also marks his last physical appearance in the timeline. He first meets Luke Skywalker when he rescues the boy from Tusken Raiders. At first Luke is reluctant to become a Jedi but agrees to be trained by Obi-Wan after his aunt and uncle are slain. Luke receives Anakin's lightsaber but is told by Obi-Wan that Anakin was killed by Darth Vader.
The two of them meet Han Solo, a reckless smuggler and mercenary, who agrees to fly them to the planet Alderaan. However, the planet is completely destroyed by the Death Star, and their ship is captured by the space station. Obi-Wan manages to get to the core of the Death Star and disables the tractor beam so the Millennium Falcon can escape. He then battles Darth Vader and ends up sacrificing himself, having become a spirit in the Force.
The Empire Strikes Back & Return of the Jedi
In the last two movies, Obi-Wan is a Force ghost and offers advice to Luke during his adventures.
Obi-Wan has been received by critics as one of the best characters in the Star Wars trilogy. He was named the 37th greatest movie hero ever by the American Film Institute.