Very little is known about his past before he joined the Varia. In a brief flashback, he was shown beating up some men while Xanxus watched. Levi participated in the Cradle Affair and remained in the Varia until Xanxus was freed.
After arriving in Japan, Levi sent his Lightning Strike Squad to hunt down the other owner of the Lightning Half Vongola Ring. However, they were stopped by Ryohei Sasagawa, Takeshi Yamamoto, and Hayato Gokudera. He later fought Lambo in the Lightning Ring Battle. Despite easily beating Lambo in both his present and teen self, Levi A Than struggled when Lambo used his Ten Year Bazooka for a second time. However, the five minute time limit of the Bazooka's effect won him the match and it was only Tsuna's intervention that stopped him from killing Lambo. Later, during the Sky Ring Battle, Levi (along with the other Guardians) was incapacitated by the Death Hitter Poison. Xanxus was able to give him the antidote and he quickly attempted to kill Lambo; however, he was easily defeated by Gokudera.
Along with the rest of the Varia, Levi was present during the attack in Italy against the Millefiore. He and Lussuria split into a separate group to protect the castle while the others hunted the Funeral Wreath in command. Levi was badly wounded while fighting the enemy, but was healed by Lussuria.
The Varia later arrived in Japan and rescued Lal Mirch, Gokudera and Gamma from the Six Funeral Wreaths. Levi, Lussuria, and Belphegor fought Bluebell and appeared to be killed. However, they were later revealed to be illusions created by Future Mukuro Rokudo. Later, along with everyone else present, Levi had his Dying Will Flames drained by Ghost.
Levi A Than first went with the Varia to France to recruit Fran. While there, he commented that M.M. was cute, but M.M. replied that if he wanted to go on a date with her, it would cost 10 billion. Later, Levi A Than was seen walking in Japan along with the other main Varia members, with Dino watching them. The Varia and Dino stayed at the same hotel. When Dino invited Reborn and Tsuna to go there and have dinner with him, Belphegor kidnapped Tsuna and quickly ran into Varia's room, asking where Xanxus was. At that moment, Levi A Than was naked and dancing because of the alcohol he had drunk.
He is last seen with the other Varia members when Tsuna thinks of the people he (Tsuna) can rely on.