Nomo was born into the working-class Osaka family of Shizuo, a fisherman and postal worker, and Kayoko, a part-time supermarket employee. As a youth, Nomo was shy and withdrawn, although passionate about baseball. He developed his corkscrew-style pitching motion in order to impress his father while playing catch. He believed that rotating from having his back turned to his target would help him add speed to his pitches.

Nomo began to struggle again in 2004. After undergoing shoulder surgery in October 2003, he was benched after going 4-11 with an 8.25 ERA for the Dodgers (the worst ERA in the history of baseball for a player with at least 15 decisions in a season). Before the start of spring training for 2005, he signed a $800,000 contract with the Tampa Bay Devil Rays. The contract also included a $700,000 incentive that kicked in if Nomo started 20 games. The stipulation was allegedly included because Devil Rays upper management was unsure if Nomo had fully recovered from his injury. After a poor start in which he posted a 7.24 ERA, he was released on July 25. Coincidentally or not, this was two days before he was slated to make his twentieth major league start. On July 27, Nomo was picked up off waivers by the New York Yankees, who signed him to a minor league contract, but never recalled him. Nomo was signed to a minor league contract by the Chicago White Sox during spring training in 2006 to play for the Triple-A Charlotte Knights of the International League, but the White Sox released him on June 7 of that year. In 2007, Nomo signed on with the Leones del Caracas of the Venezuelan Winter League, managed by his former catcher, Carlos Hernandez. His participation in the Venezuelan league was viewed as a first step toward an eventual Major League comeback. He made his debut on October 20, 2007, against Tiburones de La Guaira. Nomo pitched one inning, allowing one hit and no runs. On January 4, 2008, Nomo signed a minor league contract for 2008 with the Kansas City Royals. If added to the roster Nomo would have received a $600,000 one-year contract and the chance to earn $100,000 in performance bonuses. On April 5, his contract was bought by the Royals and was added to the 25-man roster. On April 10, Nomo made his first major league appearance since 2005. He faced the New York Yankees in relief. He was brought in to start the seventh inning of a game while the Yankees were leading 4-1. Nomo loaded the bases, but was able to retire his native countryman, Hideki Matsui, to strand all three runners. However, he later surrendered back-to-back homers to Alex Rodriguez and Jorge Posada in the ninth inning. On April 20, Nomo was designated for assignment. The Royals released him on April 29, 2008. On July 17, 2008, Nomo officially announced his retirement from Major League Baseball.

How did he perform?
However, he later surrendered back-to-back homers to Alex Rodriguez and Jorge Posada in the ninth inning.