- Bats Right, Throws Right
- Height 5' 11", Weight 160 lb.
- High School Toyodai Himeji High School
- School Ritsumeikan University
- Debut April 5, 1997
- Final Game September 28, 2005
- Born August 1, 1968 in Kobe, Japan
Taught how to pitch by his grandfather, Shigetoshi Hasegawa twice led his high school team to the Koshien Tournament, once bringing them to the quarterfinals. In college, he won 40 games, second in the Kansai Scholastic League. As a college all-star he went to the USA and "instantly fell in love with it" (quote from "The Meaning of Ichiro") due to the freedom and golf courses available. He decided to become the second Japanese player to appear in Major League Baseball, after Masanori Murakami, but Hideo Nomo beat him to it.
He helped the Japanese national team to a Silver Medal in the 1990 Goodwill Games. A first-round draft pick of the Orix Blue Wave in 1990, Hasegawa went 12-9 with one save and a 3.55 ERA in 1991. He was named Pacific League Rookie of the Year. Orix pitching coach Jim Colborn taught Hasegawa to use the changeup frequently when most Japanese pitchers did not employ it. Hasegawa mixed it in with his fastball, slider and forkball. In 1992 he went 6-8 with 1 save and a 3.27 ERA then went 12-6, 2.71 in 1993 and finished fourth in ERA. In 1994 Hasegawa went 11-9 with one save and a 3.40 ERA, second behind only Hideki Irabu. His 3 shutouts were the highest mark in the league.
1995 was a good year for Shiggy. He went 12-7 with a 2.89 ERA as a key member of an Orix staff that took the team to the club's first Japan Series. He tied for third in the Pacific League in victories and made his only All-Star team in his time in Nippon Pro Baseball. He did have one bad moment, when he allowed a PL-record 19 hits in a game on June 13. Colborn left the team before the year, though, and Hasegawa began requesting that he be allowed to go to the USA to play. When he was toasted in 1996 (4-6, 1 Sv, 5.34) and had the worst year of any starter on an otherwise dominant Orix team as the Blue Wave won their first Japan Series. Given Hasegawa's poor play, the team gave him his shot to play in the USA, selling him to the Anaheim Angels. Shiggy had gone 57-45 with 4 saves and a 3.33 ERA in his time in NPB, clearly one of the lesser Japanese players to test the US waters and a player who showed that NPB journeymen could fare well in the USA.
Hasegawa failed to make the Angels as a starter in 1997 but he did join the club in the bullpen and he had a bounce-back season, going 3-7 with a 3.93 ERA (116 ERA+). Due to his role as a middle reliever, the Japanese media pressure was minimal. Shigetoshi had ERA+s from 116 to 150 in four of his five years with Anaheim. Troy Percival helped Hasegawa with weight training and his fastball improved from the mid-80s to 93 mph. He earned his first Major League win on April 15, 1997.
When he tore a rotator cuff in 2001, he left Anaheim and joined the Seattle Mariners as the team's third Japanese player. When Kazuhiro Sasaki was injured in 2003, Hasegawa took over as closer and made his second All-Star team 9 years after his one NPB trip. He had a 300 ERA+ that year, with a 1.48 ERA. He did not fare as well the next two years but remained a solid reliever. After some discussion, Shiggy retired after 15 years as a pro baseball player. In the USA he had gone 45-44 with 33 saves and a 3.71 ERA and many other good non-stars from Japan followed Hasegawa's trail to the majors.
A collection of Hasegawa's broken-English interviews (called "My Way to Study English") became a best-seller in Japan. Hasegawa also wrote a book called "Adjustment" in which he blasted Japanese workloads for young pitchers and the poor weight training there, which he blamed for his 2001 injury (he also said American workloads for pitchers were too lenient, seeking a middle way). He also wrote a best-seller on self-management, for three books published in the last ten years of his pitching career. After his retirement, he became involved in teaching youth baseball in Japan. In December 2011, he coached an All-Star team of Japanese high schoolers who traveled to Compton, CA for a series of games against players in Major League Baseball's Urban Youth Academy.
- AL All-Star (2003)