Cara Castillo is a fictional character from the original ABC and The Online Network soap opera, All My Children. Amanda Hall Rogers portrayed the character for two episodes on June 9 and June 10, 2003, before being written off. The character was reintroduced, portrayed by actress Lindsay Hartley on December 9, 2010, until the series finale on September 23, 2011. In December 2012, it was announced that Hartley would reprise the role for the impending online reboot on April 29, 2013.

Lindsay Hartley is a veteran of daytime having been a cast member of the NBC and DirecTV soap opera Passions for its entire run from 1999 to 2008. Following a short break from the genre, Hartley was cast on NBC's long-running soap Days of Our Lives as former undercover agent Arianna Hernandez from 2009 to 2010 before being let go. However, a month later she began appearing on All My Children as Cara Castillo, a doctor who shared a past with Dr. Jake Martin (Ricky Paull Goldin). Following her exit from Days, Hartley's manager contacted AMC, as well as other soaps based in the Los Angeles area, when the show's executive producer Julie Hanan Carruthers and casting director Judy Wilson asked to meet with the actress to cast her in a new role.

In a November 3, 2010, interview with TV Guide reporter Michael Logan, Hartley discussed the development of her character.

"I love this character. She's not a girl. I feel like she's the first truly mature woman I've had a chance to play. You find out [Cara and Jake] fell in love while working in Africa with Doctors Without Borders and they got married but something went down and Cara took off with another man. At least that's what Jake believes happened, and that's what the audience will believe. Then there's the truth, which will slowly unravel."

—Hartley, TV Guide

Carolyn Finn first comes to town in 2003 with her fiancé Jake Martin to meet his family and announce their engagement. The two of them met each other while working with Doctors Without Borders. They eventually marry and leave for Africa to serve with Doctors Without Borders. When Jake comes back to Pine Valley in 2008, he reveals that Carolyn has left him for a truck driver and that they're no longer together.

In November 2010, Jake received an e-mail for a job offer with Doctors Without Borders. When his brother, Tad, comes up, he reveals that he got the offer from "Cara" − as in Carolyn. Jake tells Tad that this is the first time he's heard from Cara since she left him, and it's clear he's still hurt by what he saw as a betrayal. A few days later, Griffin Castillo shows up in town. Jake takes one look at him, and punches him. Later, he reveals to Tad that Griffin was the man he saw Cara drive off with. Griffin claims that he hasn't heard from Cara since then, but later, it's clear the two are still close. Cara soon shows up in Pine Valley, and makes her way to Krystal's to meet Griffin. While there, she sees Amanda Martin walk in and while she's chatting with owner Krystal Carey, Cara realizes that Amanda is Jake's wife and the mother of his son. It became obvious that Cara's return meant that Amanda needed to fight for her marriage.

Cara later goes to the hospital to try to convince Jake again to return to Doctors Without Borders, and that's where Tad comes in and reveals that Griffin is not Cara's lover but that he's her brother. Cara's last name is actually Castillo, not Finn. Cara tells Jake that she wanted out of the marriage, so she asked Griffin to help stage a situation so that Jake would leave her completely. When she later tells Griffin about this, she tells him she lied to Jake about why she left. Cara finds out that she can't leave the country due to a problem with her immigration papers. Cara decides to get a job at Pine Valley Hospital when she finds out they are short-staffed and after Jake says he doesn't have a problem working with her. Though Cara insists that she no longer has feelings for Jake, she is revealed to have kept their wedding rings.