Tico was first seen chained up in the Santi vault in Puerto Rico by Jessica Buchanan. He told her he had been left there to die, and she immediately took him to the hospital. It was soon learned that he was the son of Manuel Santi, which made him Antonio Vega's cousin. While Tico was in the hospital, Antonio saved his life when a gunman came after him, determined to make the family of Jaime Padilla's killer pay for his death. At this time, Tico and Sonia revealed that they were brother and sister via adoption. Tico quickly became enamored of Jessica Buchanan, and the two became close, sharing stories about their horrible fathers (his being Manuel Santi, hers being Mitch Lawrence). Tico went back to Llanview with Jessica and Antonio, and was delighted to meet his younger half-sister, Adriana. He began making a life for himself there, and the first thing that Tico did was buy Lion's Heart, the mansion formerly owned by Mitch Lawrence. He further cemented his relationship with Jessica by helping her get over her fear of Mitch's old home, while conspiring with Sonia to break up Antonio and Jessica permanently so that they could hook up with the two.
Tico also involved himself in the relationship of his half-sister, Adriana, with River Carpenter. He didn't like the way River made Adriana feel, or the fact that he was practically cheating on Adriana with Shannon McBain, so when River attempted to contact Adriana after she found him with Shannon, Tico deliberately got between the two, threatening River unless he left Adriana alone. While River was auditioning for Juilliard, Tico arranged to have River accepted, because he had picked someone better out for Adriana. It was soon clear that there were dark things in Tico's past that he didn't want anyone to know. His former nanny, Angelina Paredes, was living with him, and it was clear that Angelina was worried about something. Tico could see it too, and warned Sonia that she needed to control Angelina better, but also warned her that she is to treat Angelina with respect at all times. After Antonio and Carlotta are kidnapped and held for ransom for the Santi family money (the money was left to Antonio, and only Antonio could access it with his handprint), Tico's true nature was revealed when the money Antonio retrieved was later handed over to Tico, which Antonio observed.
After Angelina was shot with a bullet intended for Antonio, Tico swore to Sonia that he had nothing to do with the shooting, and said he was just as concerned as she was. He later met with the man who stole the bonds for him and threatened him with a knife before the man was later found dead. After planting Octavio Vigil's file on Antonio to make Antonio look even worse in the eyes of the local police, Tico met with Kevin Buchanan, and offered him his support in making certain that Kevin would become lieutenant governor again. Once Antonio uncovered the truth (that he was Manuel Santi's oldest son), he attacked Tico, demanding to know if Tico had known the truth all along. Tico eventually admitted that Angelina (who was really Isabella Santi) had sworn him to secrecy, and he had always kept that secret to protect his mother. Once Tico realized that Antonio suspected him of being El Tiburón, he had Antonio kidnapped and tied up while calling (using a voice alteration device) to give Antonio instructions ... while at the same time escorting Jessica to the charity gala he had been helping her to plan in recent weeks.
At the gala, Tico and Jessica danced, and even kissed. Jessica ran off to meet Antonio, but once she returned, Tico asked her to marry him. Although she left quickly after that, it wasn't long before she agreed to become his wife. The marriage went off almost without a hitch (Antonio tried to stop it but Jessica went through with the wedding), and when Jessica was unable to make love, Tico agreed to wait. While waiting for his wife, Tico continued his crimes as El Tiburón, and it wasn't long before people around him realized that Tico had not only killed his father and mother, but he was also responsible for the 'death' of Cristian Vega, which was really a kidnap operation that was exposed when Cristian made his way back to Llanview. On the night of the election, Tico attempted to blackmail Antonio into killing Brooks by kidnapping Cristian, but Antonio fired at Tico instead. After kidnapping Jessica and running from the police, Tico was finally taken down by John McBain. After being admitted to the hospital, Tico was put on life support, but that night someone pulled the plug. (That someone was later revealed to be Cristian Vega.)