In the Philippine Amateur Basketball League, Jack saw action for Hope Cigarettes, YCO Shine Masters and MIESCOR.

He was part of the Philippine national team that took home the bronze medal during the 1986 Asian Games in Seoul, Korea.

Under coach Baby Dalupan, Big Jack was a revelation in the 1990 All-Filipino Conference but still could not find his place with Purefoods, averaging only nine minutes per game.

Midway in the first conference of the 1991 PBA season, Tanuan was lured away by Swift Mighty Meaties from Purefoods through the offer sheet.

Before the start of the second conference of the 1993 PBA season, Tanuan was traded by Swift to Sta.Lucia Realtors for Zaldy Realubit.