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.
In "Pilot", She's first seen in the CNRI office when a breaking news report comes on about Oliver being found is broadcasted it also mentions Sara's supposed fate which causes Laurel to angrily turn off the Tv leaving Joanna concerned for Laurel.
In "Honor Thy Father", She helps Laurel with her current case.
In "Lone Gunmen", She tries to get Laurel to loosen up by taking her to Max Fuller's club, Poison. She is also the one who convinced Laurel to allow Tommy to host a fundraiser for the office after their largest donor pulled out.
In "Burned", her brother Danny is killed on duty while putting out a fire. The fire dept. said that he died from exposure to fire, but she believes he was murdered, due from the fact that firefighter's suits are designed to with stand the heat and fire burns. After Garfield Lynns's Death she move 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. She sees The Hood as a guardian angel.
In "Tremors", now working at a private law firm. She meets with Laurel about a possible job offer. She tells Laurel that the firm cannot hire her, as one of the firm's partners is aware that Laurel is being disbarred, and offers 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.