Neo is the main protagonist from the Matrix franchise. He is "The One", destined to save the human race from the machines. His real name is Thomas Anderson.
In The Matrix, he is man named Thomas Anderson, who leads a double life. In one life, he is an office employee by day and a hacker under the alias, Neo, by night. One night, he meets with a hacker, Trinity, to tell about the Matrix. The next day, he is captured by Agents led by Smith. They planted him with a tracking device to track down Morpheus, a wanted criminal. After freed from the tracking device and getting out of the Matrix, Neo is trained from fighting skills to explanation of the Agents. He goes to the Matrix and meets with the Oracle, who tells him that he may have a choice of saving someone who is captured. When Morpheus is captured by the Agents, Neo, along with Trinity, decided to save him and storm in a military-controlled building to rescue Morpheus. After rescuing Morpheus, Neo gets into a fight with Smith, but instead of running away, he fights him. He is victorious, but Smith possesses another human body and Neo runs away from him and his henchmen, Agents Brown and Jones. Just as Neo is about to leave the Matrix, he is shot to death by Smith and dies. Trinity kisses him and Neo is revived as The One. He managed to stop the bullets and destroy Smith by phasing through him. After leaving the Matrix, Neo and Trinity kiss. Inside the Matrix, Neo leaves a message to the machines and flies away.
In The Matrix Reloaded, Neo is called to be the savior of the human race. Inside the Matrix, he finds out that the Oracle is a program, so is Seraph. After talking to Oracle, Neo encounters Smith, who appears as a free program because of having Neo's part that causes him to rebel against the machines like him. He fights an army of Smiths, but runs away because he can't fight a lot of them. Afterwards, Neo and the gang goes to the Merovingian, who is a rogue program. After Neo defeated his henchmen, Merovingian retreats. Neo encounters Smith again, but escapes. He meets with the Architect, who gives him a choice: go to the Source and save Zion or go back to Matrix to save Trinity, who is dying by the hands of the Upgraded Agents. Because of his love for Trinity, Neo chooses to save her and goes back to the Matrix to save her. He manages to remove the bullet from her heart and revive her. In the real world, Neo has stopped the sentinels by electronic disruption and fainted.
In The Matrix Revolutions, Neo is revealed to be inside the Matrix without being connected. While there, he is trapped in a train station by the Trainman, a rogue program working for Merovingian. After Trinity manages to free him, Neo goes to Oracle to tell him that Smith is growing stronger and plans to take over the Matrix. When Neo asks her what is Smith, she tells him that Smith is him, his opposite, and negative. Upon going back to the real world, Neo volunteers to go with Trinity to the Machine City. While going there, he encounters Smith, who possesses Bane and the two fight. Neo has ended up being blind during the fight, but he can see not only Smith, but also the machines. Upon going to Machine City, Neo has managed to stop the sentinels, but Trinity is killed after landing to the city. Neo teams up with Deus Ex Machina that in exchange for stopping Smith, humans and machines will have to make peace. He is connected to the machine god and battles Smith for the last time. Realizing that he can't beat him and remembering Oracle's words "everything has beginning has an end", Neo allows Smith to make a copy from himself. However, as Neo is connected to Deus Ex Machina, he is destroyed, along with Smith. His body is last shown taken by the machines.
Neo plays a very small role in the ' Kid's Story' portion of The Animatrix.