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.
Working at the CNRI
Joanna was at the CNRI office when a breaking news report came on 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 Laurel.
Jo tried to get Laurel to loosen up by taking her to Max Fuller's club, Poison. She was also the one who convinced Laurel to allow Tommy to host a fundraiser for the office after their largest donor pulled out.
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 from the fact that firefighter's suits are designed to withstand the heat and fire burns. After Garfield Lynns' death she moved back with her mother and while saying goodbye to Laurel she asked her to find a way to give Danny's fire badge to The Hood, as she viewed the vigilate as a guardian angel.
Helping a friend
Moving on to a private law firm, she met with Laurel about a possible job offer. 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.
Joanna is described as "more cynical" and "less idealistic" than Laurel. Stemming from this, she convinced Laurel to allow Tommy to throw a fundraiser for their law firm.