|Marital Status||Married to Marina Hernandez|
|First Appearance||Human Error|
We first see Esteban when the U.S. Coast Guard is trying to rescue he and Marina from their disabled boat during a storm. Estaban has a suitcase which he refuses to relinquish, but with it the helicopter's recovery cable can't handle the combined weight. He eventually is forced to drop the suitcase, which sinks into the Atlantic. He is rescued, but explains in Spanish to the crew that the case contained Marina's medical records. When he continues to speak in Spanish, the crew thinks he wants to go home, but he switches to English and explains that he wants to see Dr. House.
After Marina is admitted to Princeton-Plainsboro Teaching Hospital, House orders both Marina and Esteban to be examined so that Esteban's symptoms can be eliminated from his wife's symptoms. Robert Chase is assigned to examine him. When Esteban asks when he gets to see House, Chase tells him that House rarely sees anyone. When Esteban says he came all the way from Cuba, Chase explains House doesn't care and that's the doctor he chose.
When the team starts treating Marina for multiple sclerosis, Esteban is incredulous, believing that if it was MS the doctors in Cuba would have been able to diagnose it.
When Marina doesn't respond to treatment, House instructs Eric Foreman and Allison Cameron to do a cardiac catheterization. House refuses to deal with Esteban and Foreman is angered that House is sticking him with overnight shifts during his last week. To get back at House, Foreman gives Esteban House's home phone number and tells him to call it a lot because sometimes it takes House a few calls to respond.
When House returns that night, Foreman and he get into a fight about whether House should have just spoken to Esteban. However, when they do the catheterization, Marina suffers from cardiac arrest and doesn't respond to defibrillation. House tells Cameron and Foreman not to put Marina on heart-lung bypass because it might cause a clot, so they start a marathon session of CPR. Meanwhile Esteban, who thought the procedure would only take forty-five minutes, keeps asking the nurses about Marina.
Eventually, House feels that he has done everything he can and has to tell Esteban that they can't get Marina's heart started. Esteban agrees to take her off bypass. However, when the machine is turned off, Esteban tells House he can feel a pulse. House writes it off as residual momentum of the blood, but when he turns on the monitors, they show a normal sinus rhythm and Marina is soon conscious.
House still thinks that something is wrong with Marina and has to convince her and Esteban to try the heart catheterization again. They are reluctant, but House convinces them by reminding them that although she seems to be fine, there is probably still a hidden heart defect.
However, the rest of House's team soon has all quit or resigned. House and Esteban sit in Marina's hospital room drinking and smoking cigars. House appears to have formed a friendly bond with Esteban, and they joke about whether or not Marina is sleeping. When Esteban asks if House is sad his team is all gone, he says he isn't.