''What wouldst thou know, my Queen?'' The following article you are about to observe contains spoilers that have yet to be seen worldwide. Should you choose to continue, the secrets you will learn cannot be forgotten.
Many years ago, Héctor was a passionate musician from Santa Cecilia, born there in 1900. When Héctor was 18 years old, he met a woman named Imelda. Their shared talent in music sparked a romance, and they fell in love, married, and had a daughter named Coco. Héctor loved Coco dearly and wrote the song "Remember Me" for her. While Imelda was ready to settle down and plant roots for their family, Héctor still wanted to give his songs to the world. So he set out on tour with his best friend Ernesto de la Cruz. Héctor wrote the songs and Ernesto sang them. During the tour, Héctor began to feel homesick to the point where he came around to Imelda's way of thinking and decided to go home. When he told Ernesto, they had an argument where Ernesto begged him to stay as he needed his songs but Héctor was unmoved. Ernesto offered to send him off with a toast saying he would move heaven and earth for his amigo. On his way to the train station, Héctor suddenly collapsed and died as Ernesto spiked his toast with poison earlier.
During his time in the Land of the Dead, Héctor learned how Ernesto took credit for his songs. When Imelda died, she refused to welcome Héctor back to the Riveras. Estranged from his family, Héctor spent his years trying to cross over to the Land of the Living to see Coco but he was rejected as his family wouldn't put his picture up.
Spoilers end here.
Héctor is a charming trickster in the Land of the Dead who is forced to enlist help from Miguel to visit the Land of the Living.
Héctor first appears trying to cross over to the Land of the Living disguised as Frida Kahlo. The agent quickly checks that he isn't recognized on his family's ofrenda, leading Héctor to make a run for it. But his hopes are in vain, as he ends up sinking into the marigold petals and is arrested. At the Grand Central Station, Héctor is left off with a warning by the officer. After leaving, Héctor meets a living boy named Miguel who, having overheard that Héctor knows Ernesto de la Cruz, asks Héctor to take him to Ernesto to receive his blessing so he can go home. Héctor tells him he will get him to de la Cruz if he puts his portrait up on an ofrenda so he can cross over and Miguel agrees.
They discover there's a music contest where the winner will get to enter de la Cruz's mansion. After getting a guitar, Miguel enters the contest. During the contest, Héctor learns that Miguel lied to him about de la Cruz being his only family. Héctor scolds Miguel for leaving his family worried sick and attempts to bring Miguel to them, but this makes Miguel go off to find Ernesto himself.
Later, Héctor (disguised as Frida again) sneaks into his old partner's mansion and finds Miguel with Ernesto. Hector reveals to Miguel that he wrote the songs Ernesto is famous for and reminds him of their deal. As Héctor reminds Ernesto of the heaven and earth statement, Miguel points to one of the films Ernesto brought back from one of his trips to the Land of the Living which has the same line. Watching the film, Héctor remembers his last night alive and realizes that Ernesto murdered him and stole his song book and guitar. Ernesto takes Héctor's portrait and has Miguel and Héctor thrown into a cenote.
As Héctor laments about Coco, Miguel realizes that the picture he is been carrying was Coco with Héctor, and they discover that Héctor is Miguel's great-great-grandfather, not Ernesto. They rejoice the revelation, although they remain trapped in the ceneto; at that second, they are discovered by Miguel's dog Dante and saved by the other Riveras. Héctor also sees Imelda among them and tries to apologize to her, however he starts fading in and out, as Coco is in danger of forgetting about Héctor. Imelda, Miguel, and the other Riveras learn that they need to get Héctor's portrait back from Ernesto or he will be lost.
At the concert Ernesto is performing at, the Riveras get the portrait back. Héctor manages to finally reconcile with Imelda and together they prepare to give Miguel her blessing to return home, however Ernesto interrupts the ceremony to drop Miguel from the building. Héctor tries to stop him, but collapses on the verge of disappearing. Miguel is saved at the last minute by Pepita, but the photo is lost in the water. However, Ernesto's crimes are exposed to the Land of the Dead. As sunrise approaches, Héctor starts to fade away and Miguel is almost a skeleton himself. Miguel refuses to leave Héctor behind until he is forced to accept Imelda's blessing, which sends Miguel home.
Thanks to Miguel, Coco remembers Héctor through "Remember Me", saving Héctor. With the identity of her father revealed to the Rivera family, Héctor has a picture of himself placed on the ofrenda. The following year, Héctor has at last received the recognition he deserves and has reunited with a recently deceased Coco. Together with his family, Héctor finally crosses over to the Land of the Living during Día de Muertos, where he joins Miguel in a guitar duet with a spiritual version of his guitar.
Héctor is one of the six characters in the movie to be voiced by the same actor in both the English and Latin American Spanish dubs of the film, the others being Julio Rivera, the Departure Agent, the Security Guard, Tío Berto, and Luisa Rivera.