Anna Williams was featured in Nina's Arcade mode ending, in which she accuses Nina of stealing one of her shoes. She was also featured as Nina's sub-boss in Tekken, but did not become a usable character until the console version of the game. Anna, like all of the other sub-bosses in the first Tekken game, was not given an ending.

As in the first tournament, Nina was once again hired to assassinate the sponsor of the current tournament, Kazuya Mishima. Whether at Kazuya's discretion or Anna's own volition, Anna became a bodyguard for Kazuya, along with Ganryu and Bruce Irvin, who were all charged with Kazuya's protection. It is likely that Anna's intervention prevented her sister from carrying out her contract, and Nina was later captured by Mishima Zaibatsu forces and used in Doctor Boskonovitch's cryonics ("cold-sleep") research. Learning about this, Anna volunteered to be another test subject, requesting that she be woken in the future at the same time as Nina. Her reasons for doing so remain ambiguous, though the game suggests that Anna would have felt lonely without Nina and/or jealous at the thought of her sister's youth being preserved.

After being placed in suspended animation during the second tournament, Nina was awoken 18 years later by the influence of the recently excavated Ogre, who compelled her to assassinate Jin Kazama. As per her request, Anna was awoken at the same time as her sister, though she was unaffected by Ogre's influence. Nina also began to suffer ill effects from the "cold-sleep," resulting in long term memory loss. In an act of compassion, Anna set out to stop Nina from once again becoming an assassin, and to help her recover her memory loss.

Nina decides to make contact with Anna in hopes of restoring her memory. Unfortunately, their meeting triggers Nina's lost feelings of hostility towards her sister, and she immediately opens fire. Anna retaliates, and the reunion descends into a gunfight which lasts for days. The sisters eventually reach a stalemate and agree to settle things for good at The King of Iron Fist Tournament 5. A portion of their gunfight can be seen in the introductory sequence of the game.

After being defeated by her sister Nina, Anna seeks revenge. However, Nina has already gone into hiding. Anna hears rumors she has become Jin Kazama's new bodyguard, thus being involved with the Mishima Zaibatsu, so Anna decides to join forces with G Corporation.