Hayashi retired from in-ring competition in July 2024, and since then has maintained his role as Gleat's chief technical officer.

As Shiryu, he was part of the memorable rudo group, Kaientai Deluxe, which waged war with Michinoku Pro's Sekigun for many years, producing some classic matches.

In June 1997, he left Michinoku Pro for the Mexican Promo Azteca promotion, before joining World Championship Wrestling (WCW) in the United States in October of that year.

In late 1999, Vince Russo and Ed Ferrara began booking WCW programs and Hayashi was paired with La Parka.

During interviews, the two would speak in their native languages which would be humorously dubbed over by charismatic English speakers, calling him names such as "The Kaz Master" and "Kazanova".

Primarily feuding with 3 Count, the Jung Dragons consisted of high-flying cruiserweight talent and gained considerable popularity until the group's demise the following year.

During this time, he became friends with Keiji Mutoh, who was appearing in his final run with the promotion under his Great Muta guise.

Nobutaka Araya joined the team after six-man Action between Mexico Amigos and Araya/Fuchi/Hirai at the Carnival's final show.

On February 6, 2009, Hayashi defeated Naomichi Marufuji to win the World Junior Heavyweight Championship for a second time.

[5] In June 2013, Hayashi announced his resignation from All Japan in the aftermath of Nobuo Shiraishi taking over as the president and Keiji Mutoh leaving the promotion.

[16] On November 30, Hayashi and Kondo first defeated Kai and Ryota Hama in the semifinals and then Akira and Manabu Soya in the finals to win the tournament and become the inaugural Wrestle-1 Tag Team Champions.

[19] On January 31, 2016, Hayashi, Minoru Tanaka and Tajiri won the vacant UWA World Trios Championship.