He was best known for his performances as Rei in Fist of the North Star, M'Quve in Mobile Suit Gundam, Buriburizaemon in Crayon Shin-chan, D in Vampire Hunter D, Cyborg Ninja in Metal Gear, Paul von Oberstein in Legend of the Galactic Heroes, Devimon in Digimon, Prince Demande in Sailor Moon, Vega in Street Fighter, R. Ichiro Tanaka in Kyūkyoku Chōjin R, Inspector Ninzaburo Shiratori in Detective Conan, Zato-1 in Guilty Gear, Hyo Imawano in Rival Schools and Luke Skywalker in Star Wars.

On May 9, 2000, at 4pm, Shiozawa fell down the stairs of his home in Shinjuku, Tokyo, claiming that there were no injuries found on him, he insisted that he was fine.

Six hours later, at 10pm, Shiozawa's body condition suddenly changed, he collapsed and was rushed to the Tokyo Medical University Hospital; he died of a cerebral contusion at 12am on May 10, at the age of 46.

Zato-1 was replaced by the shadow parasite Eddie (voiced by Takehito Koyasu), who took over Zato's body following his death until Guilty Gear Xrd.

In 2016, a well-known voice actor, Hiroshi Kamiya, has permanently taken over the role for Buriburizaemon from Crayon Shin-chan, after being remained silent for 16 years, due to Shiozawa's passing.