Long, long ago, during the Silver Millennium, Lita lived as the Princess of Jupiter. All was well until Queen Beryl and the Negaverse attacked, destroying the Moon Kingdom. Princess Serenity's mother, Queen Serenity (go figure) used the Silver Imperium Crystal to send them all to the future to be reincarnated.
In the present timeline, Lita's parents died in an airplane crash when she was young, leaving her to live in an apartment alone off of insurance and her trust fund. Lita arrived at Crossroads Junior High after supposedly being kicked out of her previous school for fighting, which made most of the students wary to forge a friendship with her. However, Serena soon befriended the new girl. Luna realized that Lita was Sailor Jupiter when Game Machine Joe was transformed into a monster and Lita tried to help out in the battle, the symbol of Jupiter appearing on her forehead.
After defeating the Negaverse and Queen Beryl, she lost all of her memories of being Sailor Jupiter and didn't remember until Alan and Ann attacked her at an audition and Luna restored her memories, as well as the other three inner scouts.