In the anthology of solo JSA stories in All-Star Comics # 3, each member has a leading lady in his adventure. For the Flash it was Joan Williams. While Superman had his Lois, the Flash had his Joan. She was a fixture in Flash Comics from the first issue in 1939 which featured the inaugural appearance of the Flash. Joan was a regular in that title as well as in All-Flash (originally All-Flash Quarterly), the first issue of which told the Flash's origin story, updated for the post-crisis continuity in Secret Origins # 9 (published 1986). All-Star Comics #2 and 3 were Joan's first appearances outside Flash titles.
Joan appeared in the June 1941 retcon tale in All-Star Squadron Annual # 3 when she and a number of heroes and supporting characters were bathed in a ray that significantly slowed their aging process. Joan's next retcon appearance was when the crisis of 1985 came to 1942 in All-Star Squadron #54. The year 1942 is when Joan began appearing alongside Flash in Comic Cavalcade. The two also appeared in the 1944 one-shot Big All-American Comic Book. The Flash (Jay Garrick) and Joan continued to appear together in the Flash books until 1949. They were married at some point prior to the JSA's retirement in 1951. The retirement was due to a Congressional investigation of the team as told in the retcon stories of Adventure Comics # 466 (1979) and the mini-series America vs. the Justice Society (1985).
The first Silver Age appearance of Jay and Joan Garrick was in Flash # 123, the famous 1961 Flash of Two Worlds Story. Jay and Joan made occasional guest appearances in the revived Flash comic from 1961 through 1982. Joan also appeared with Jay in the revival of All-Star Comics # 61 (1976) and 73 (1978). Joan has since been a recurring character in most Flash and JSA titles.