When Irabu refused to play for San Diego, they traded him to the Yankees, and the aftermath of the deal led to the development of the posting system.

His father was a U.S. Air Force meteorologist named Steve Thompson, married to a woman in the United States at the time.

Thompson, who had been redeployed to Vietnam before his son's birth, briefly visited young Hideki and his mother a year later, but they would not again meet until after Irabu reached the U.S. major leagues.

This was the fastest clocked pitch in all of Japanese Professional Baseball (NPB) until 2005, when the record was broken by Marc Kroon of the Yokohama BayStars.

For the negotiating rights to Irabu, the Yankees offered the Padres a choice of one from a list of players including Brian Boehringer, David Weathers, Chris Cumberland, Andy Fox and Matt Luke.

[9] The Padres eventually included him as a player-to-be-named-later in a trade that involved Homer Bush and Irabu going to the New York Yankees in exchange for Rafael Medina, Rubén Rivera, and $3 million in cash.

[12][13] Irabu made his highly publicized debut on 10 July 1997, drawing almost twice as many fans that night as they averaged for weeknight games.

George Steinbrenner publicly expressed disgust at his weight, at one point calling him a "fat pussy toad"[15] after he failed to cover first base on a ground ball during a spring training game.

[21][22] Before the 2004 season, he pitched in the 2004 MLB Japan Opening Series exhibition games against the Tampa Bay Devil Rays.

In August, he announced his intention to return to the Japanese professional leagues, and began playing for the semi-professional Kōchi Fighting Dogs.