Joanna "Jo" de la Vega is a legal aid attorney at Wethersby & Stone LLP. She is the daughter of an unnamed woman, the sister of the late Danny de la Vega and the best friend and former co-worker of the late Laurel Lance at the CNRI. She is also one of The Arrow's supporters.
At some point in law school, Joanna met and befriended Laurel Lance. After graduation, the two of them went on to work together at City Necessary Resources Initiative (CNRI), a legal aid office in The Glades.
Working at the CNRI
At CNRI, Joanna was discussing a case against Adam Hunt with Laurel, warning her of their slim chances of winning, when a breaking news report about Oliver Queen being found was broadcasted. It also mentioned Sara Lance's supposed fate, which caused Laurel to angrily turn off the TV, leaving Joanna concerned for her friend.
The next day, Joanna informed Laurel that Hunt's lawyers arranged for them to appear in front of Judge Grell, who was in his back pocket, though Laurel remained optimistic. After The Hood distributed the money Hunt stole back to its owners, Joanna and Laurel were ecstatic, with Joanna proudly declaring the unknown individual to be Starling City's "guardian angel". She then told Laurel that Tommy Merlyn arrived to see her.
Joanna helped Laurel with her case against Martin Somers on behalf of Emily Nocenti, who wanted justice for Somers' murder of her father, Victor Nocenti. At the courthouse, the trio had an awkward encounter with Tommy and Oliver after the latter was legally resurrected. During the trial, Joanna and Emily watched as Laurel made her opening statement. The next day at CNRI, Joanna warned Emily that Somers' attorney would try to paint her as blinded by grief or looking to make money. Laurel's father, Quentin Lance, then arrived to put Laurel, Joanna and Emily under police protection until the situation with Martin and the Triad calmed down. Joanna took Emily out for coffee while Laurel and Quentin talked.
After the Hood forced Somers to confess to ordering Victor's murder, Joanna, Laurel and Emily watched as the news reported his arrest at CNRI. Joanna and Laurel happily assured Emily that the DA will be prosecuting Somers for all his crimes. Emily thanked the two before leaving.
After CNRI's largest donor, Stagg Industries, pulled out, Joanna and Laurel were concerned about how much longer the office could keep their doors open. The next day when Tommy detailed to Joanna his plan of Merlyn Global Group sponsoring a benefit for CNRI, she convinced a suspicious Laurel to take up Tommy's offer, pointing out that they needed the money. At the benefit, which was a success, Joanna and Laurel thanked Tommy for his help. Laurel admitted Joanna was right, much to the latter's satisfaction.
In January 2013, Joanna found out from Detective Quentin Lance, and fire chief Raynes that her brother Danny was killed on duty while putting out a fire. The fire department said that he died from exposure to fire, but she believed he was murdered, due to the fact that firefighter's suits are designed to withstand the heat and fire burns.
After Garfield Lynns' death, Joanna took a sabbatical from work and moved back in with her mother for the time being. Joanna bid Laurel goodbye and requested that she find a way to give Danny's fire badge to the Hood as thanks for solving his murder, expressing once more how the vigilante was a guardian angel.
Several months later in May, Joanna returned to work. That week after the Undertaking was announced, she and her coworkers headed to CNRI during the evacuations to retrieve all their files and evidences from various cases for their clients. When the earthquake started, Joanna managed to escape CNRI while Laurel was trapped. After Tommy died saving Laurel from the collapsing building, Joanna, Quentin and Laurel sadly watched the destruction.
Joana presumably attended Tommy's funeral.
Helping a friend
At some point after the Undertaking, Joanna became a legal aid attorney at a corporate law firm, Wethersby & Stone LLP.
In early 2014, Joanna met with Laurel about a possible job offer at her firm. She told Laurel that the firm could not hire her, as one of the firm's partners was aware that Laurel was being disbarred, and offered to help her fight the disbarment.
It can be assumed that Joanna attended Laurel's funeral, where the latter's identity as Black Canary was revealed.