Tidus' hometown is Zanarkand. In Zanarkand he's known as a famous and skilled Blitzball player. He's gained renown through his father Jecht, who was also a skilled blitzball players. After his father disappeared from the world of Zanarkand, the spotlight turned to Tidus to see if he could live up to his father's name. Outside of Blitzball, Tidus has a few family problems concerning his dad. Since he was so popular in the media, he often neglected both Tidus and his Tidus' mother (who's never named). Because of this Tidus developed a bond with his mother, and never got to know his father. However whenever Jecht would come home, Tidus' mother would pay no attention to him, focusing all of her time with Jecht. Because of this Tidus started to hate his father. The fact that Jecht constantly called him a cry baby, didn't help much either. In a flashback from Final Fantasy X, it's revealed that when Jecht first went missing, Tidus had wished he died, so he wouldn't have to deal with him anymore. Tidus' Mother, apparently aware of Tidus' hate for his father rationalizes saying "If he dies, you'll never be able to tell him how much you hate him." Tidus is aware that Jecht had a friend named Auron, but didn't know how he knew him, or how they became friends. Auron visits Tidus during the attack of Sin, and brings him up close. Auron claims that this is the beginning of "his story." After that, Tidus is transported to Spira.
After being transported to Spira, the first person Tidus meets is Rikku (but won't find out her name until a few hours later). He's attacked by Rikku with her crew of Al Bhed sailors, and gets knocked unconcious. When he wakes up Rikku drops several bombs on him. Such as Zanarkand being destroyed, and how it was destroyed a thousand years ago, along with a few gameplay related revelations (Such as the Sphere Grid). Since Rikku is the only person on the boat who speaks Tidus' language, he sees her as a friend, and they grow a bond. Rikku advises him to go to Spira's blitzball paradise, Luca and she promises to take him there. Shortly after, Sin attacks the Al Bhed's ship and Tidus drifts to another part of Spira.
Tidus wakes up off the coast of a beach, and is greeted by a familiar looking sports item, a blitzball. Shortly after Tidus meets Wakka, leader of the Besaid Island Aurochs, a down-on-it's-luck blitzball team. Wakka, similarly to Rikku explains many of the differences from Zanarkand and Spira. Even though Zanarkand exists in both world, apparently Tidus' Zanarkand did not have the rest of Spira, or Tidus just never knew about it. Both Wakka and Rikku blame Tidus' lack of knowledge of the world on Sin's toxins, explaining that the toxin can cause amniesa. Wakka decides to let Tidus tag along with him in hopes that seeing familar places would jog his memory. Soon after Tidus meets Lulu, a black mage guardian who acts bitterly towards Tidus at first. Kimarhi, a Ronso guardian who is indifferent to Tidus' prescence, and finally summoner Yuna. Tidus feels a strong attachment to Yuna because of her beauty, and has the suspicion that Yuna has similar feelings. Wakka picks up on this mutual attraction and warns Tidus not to get involved. Not that he paid much attention to that advice.
Yuna and her guardians start their pilgrimege as planned, and Wakka convinces the group to let Tidus comes along in hopes someone will recognize him. Lulu objects to the idea, but Yuna pleasently agrees to it. Whenever the party must travel somewhere Yuna often chooses to speak with Tidus whenever possible. Eventually Yuna asks her guardians for Tidus to become her guardian, when they all explain that he's too inexperieced she relents asking that he just "sticks around."
Later on when Auron joins the party, Auron encourages the relationship as opposed to Wakka and Lulu who are against it. Rikku also joins the party again, and acts as a good friend to Yuna and teases Tidus about his crush. As the story goes on Tidus and Yuna spend more and more time together and become more attached to each other. He also stands up for Rikku, when Wakka verbally attacks for no reason other than her being an Al Bhed. When Seymour Guado proposes to Yuna, and she accepts, Tidus expresses anger with her decision. His rage is not from possession or betrayal, but rather he doesn't believe Yuna actually loves Seymour, and therefore thinks she shouldn't marry him. Tidus is the first person to find out that Seymour Guado killed his father in order to get to his position in the world's political ladder. The party confronts Seymour, and Yuna reveals that the marriage would be to stop Seymour and his schemes, and not love.
After Yuna is kidnapped by the Al Bhed, Tidus and the rest of the party demand answers from Rikku (Who is an Al Bhed) as to why they decided to kidnap her. Rikku explains that the Al Bhed are not kidnapping summoners they're "saving" them. Tidus seems to be out of the loop and asks "saving them from what?" Rikku explains that in order for Yuna to defeat Sin, she'll die while calling the final aeon. Tidus is crushed by this news and is angered by the fact that no one told him about her destined fate. This news reveals why Lulu and Wakka were against their relationship in the first place, and explain that they tried to talk Yuna out of becoming a summoner when she first had thoughts of becoming one as a little girl. Tidus vows with Rikku that they'll find a way to defeat Sin without Yuna dying. He plans an assault on Bevelle (Spira's largest and most powerful city). He reaches the altar just before Seymour is about to kiss Yuna. Held under gunpoint he is forced to watch as Yuna kisses him. Yuna threaten's to kill herself unless her friends are released. The party escapes and meet Yuna in Bevelle's temple, where they are re-captured. After escaping from Bevelle's prison, the Via Purifico, Tidus comforts a heartbroken Yuna, deeply hurt by the temple's betrayal and the pressure of saving Spira from Sin. Tidus consoles a crying Yuna with a passionate kiss and he vows not to let her die.
It's All a Dream
Towards the end of Final Fantasy X, the Fayth (Spiritual source of the Aeons) of the Aeon Behemoth, explains Tidus is nothing more than a summoning from the collective Fayth. At first he finds this hard to accept, but he quickly understands that Yuna's mission needs to come before anything else, including his Zanarkand (which was also a summoning from the Fayth, and thus fake). After killing his father Jecht and killing off all of Yuna's aeons to get to Yu-yevon (Sin's creator). He explains to the group that he will dissapear. With the words "I know it's selfish, but this is MY STORY". After Yu-yevon and Sin are eliminated for good, he embraces Yuna one last time, before leaving for the Farplane, where he meets Braska, Auron and high-five's Jecht.
Final Fantasy X-2 Ending
The fayth allow Tidus to go back to Spira, after Yuna defeats Shuyin and Vegnagun. Under the sheer power of Yuna and Tidus' love for eachother. As long as the pair's love for each other is true, Tidus will remain in existence.
Tidus makes several cameo appearences in other games
Kingdom Hearts series
Tidus appears as an NPC alongside Selphie and Wakka on Destiny Islands, the world you start in at the beginning of Kingdom Hearts. Tidus, Selphie and Wakka also reappear in Kingdom Hearts: Chain of Memories and its enhanced remake, Re: Chain of Memories in Destiny Islands as well. However, he does not appear in Kingdom Hearts II.
Dissidia: Final Fantasy
Tidus appears as a playable character in the Final Fantasy themed fighting game, Dissidia: Final Fantasy alongside his father, Jecht.
Itadaki Street Special
Tidus also makes an appearence along with many other Dragon Quest and Final Fantasy characters in Itadaki Street Special.