Joan Williams was a student at Midwestern University, she was the girlfriend of Jay Garrick who was her classmate. But they took different ways; Joan went to Washington and Jay to New York. She was one of the people who know about his lab accident that gave him powers and when her father was kidnapped she asked Flash (Jay) to help her locate him.
When she returned to Keystone City and she and Jay married before the Society disbanded and Jay retired as Flash.
It was discovered that Joan has leukemia and she moved to Denver to an experimental treatment but she got better and they returned to Keystone.
Following the events of Flashpoint, Jay and Joan (alongside the entire Justice Society and most of Earth's Golden Age heroes in general) are relocated to the revamped Earth 2 in the DC Multiverse.
Now significantly younger, Joan appears as a recent college graduate who leaves town to start a job with the Tyler-Chem corporation. Before leaving, she exchanges harsh words with her ex-boyfriend Jay, who now appears as a slacker with no powers or job prospects.
In Other Media
Joan appears in the Young Justice animated series as the wife of Jay Garrick, who is retired from the world of superheroes. She first appears in the episode "Downtime," where she, along with Barry and Iris Allen and the West family, celebrate Jay's birthday. In season 2, she and Jay take over as the legal guardians of Bart Allen, Barry and Iris' time-displaced grandson from 40 years in the future.