In 1988, The Orient Express began as Badd Company (Paul Diamond and Pat Tanaka) in the American Wrestling Association (AWA). In the AWA they were given identical ring gear, and were accompanied by flamboyant manager Diamond Dallas Page, who always had a number of valets, known as the Diamond Dolls, with him.
The team's first feud was against The Midnight Rockers, whom they defeated for the AWA World Tag Team Championship on March 19, 1988. They held the titles for a year, and feuded heavily with Chavo and Mando Guerrero before losing their titles on March 25, 1989 to “the Olympians" (Brad Rheingans and Ken Patera). Shortly after losing their titles, they split from Page, and had a short feud against each other before wrestling in singles competition until early 1990.
In early 1990, manager Mr. Fuji split up the team known as The Powers of Pain (The Warlord and The Barbarian) as he sold their individual contracts to Slick who got the former and Bobby Heenan who received the latter, respectively. Fuji then brought in The Orient Express (Sato and Tanaka) as his latest threat to the WWF tag team division.
The Orient Express kicked off a prolonged feud with The Rockers (Shawn Michaels and Marty Jannetty) that started at WrestleMania VI, where Sato and Tanaka were victorious via countout after Sato threw salt in Jannetty's eyes while they were outside of the ring, and continued off and on for well over a year. The Orient Express got involved in the Legion of Doom (Animal and Hawk) / Demolition (Ax, Smash and later Crush) feud as Mr. Fuji managed Demolition as well. Demolition was being phased out and the Orient Express began taking on the Legion of Doom instead. The Legion of Doom / Orient Express feud was extremely onesided due to the Legion of Doom’s massive size advantage.
After WrestleMania VI, Tanaka and Sato only made two pay-per-view appearances while in the WWF. Firstly at SummerSlam 1990, where the team were defeated by "Hacksaw" Jim Duggan and Nikolai Volkoff. They were then a part of the Sgt. Slaughter-led team "The Mercenaries" (that also included Boris Zhukov at Survivor Series. Sato was pinned by Bushwhacker Butch and Tanaka was pinned by Tito Santana only moments later.
When Sato decided to leave in the latter days of 1990, the WWF decided to reunite the team known as Badd Company, only this time with Paul Diamond wearing a mask to conceal his ethnicity and using the name Kato. During this time the team had a match with their old enemies the Rockers at the 1991 Royal Rumble and another match against The New Foundation (Jim "The Anvil" Neidhart and "The Rocket" Owen Hart) at the 1992 Royal Rumble – which were the only two pay-per-view appearances for the New Orient Express.
Sato briefly rejoined the team in 1991 to team with Tanaka and Kato for a series of six-man tag team matches on WWF house shows, but Sato left the WWF after only a handful of matches together. Tanaka would leave the WWF in February 1992. Diamond went on to wrestle as a singles competitor in the WWF, first as Kato, then later as Max Moon, replacing the departed Konnan, neither gimmick meeting with very much success.
After Paul Diamond also left the WWF, the two reunited as Badd Company, working for Extreme Championship Wrestling from late 1993 to early 1994, wrestling against the likes of The Bad Breed (Ian and Axl Rotten) and The Public Enemy, but never won the ECW Tag Team Championships.
Pat Tanaka resurfaced in WCW during 1994 as a singles wrestler billed as "Tanaka-San". Paul Diamond showed up with the Kato mask on using the name "Haito" shortly afterwards. The two men even wrestled a couple of matches together, but they never achieved any notoriety in WCW and finally split up for good by the end of 1994.