Andy practices the Shiranui-ryuu ("style" in Japanese) Ninjutsu and a form of empty-handed ninja combat called Koppouken, which he trained in after witnessing his foster father's murder in order to gain revenge on Geese Howard. Mai Shiranui is his fiancée (in her mind), and the granddaughter of Hanzo Shiranui, the man he learned Ninjitsu from.

It was after his foster father Jeff's death that Tung Fu Rue took responsibility for raising himself and Terry. Andy went to Japan to train under Hanzo and grew up alongside Mai, while Terry stayed in South Town.

During Andy's time in Japan, he met the Muay Thai fighter Joe Higashi, and challenged him to a match. When Andy won, he invited Joe to return to America with him to enter the King of Fighters tournament, held by Geese. Before this, Andy had rarely, if ever, seen Terry in the interim since Jeff's death. Andy quickly grew jealous of Terry because Terry was taller, older, more experienced and quite possibly a better fighter, and unlike Andy, Terry did not practice a grueling daily training regimen.

Late in the tournament, Andy tried to kill off Geese by himself. Geese's power proved to be too much for Andy as he almost fell to his death. Terry saved Andy, who finally acknowledged Terry as the better of the two brothers.

Andy's emotions prevented him from reaching the final round, but when Terry defeated Geese, Andy felt a sense of closure and returned to Japan to continue his training. After Terry beat Geese at the end of their first King of Fighters Tournament, a new tournament was held, this time hosted by Wolfgang Krauser. Andy, while present in the tournament, did not accomplish much story-wise.

Ever since Geese's death, the fall of the First Southtown, and the birth of Second Southtown, Andy has been busy training Hokutomaru through the ways of Shiranui-ryuu Ninjutsu and Koppouken. Instead of fighting in the tournament himself, he sends Hokutomaru in his place to see what his apprentice has learned. In Hokutomaru's ending Andy writes him a note saying that he was proud of how strong Hokutomaru has gotten. Then he ended the note by saying he is no longer his teacher but his rival and that they will cross paths again.

(Source: Wikipedia)