I.R.S.

Rotunda and Windham joined the World Wrestling Federation as the U.S. Express in 1984. They won the WWF World Tag Team Championships twice, first winning them from Dick Murdoch and Adrian Adonis in January 1985. The US Express' most notable feud was with The Iron Sheik and Nikolai Volkoff, who they lost the tag titles to at the first WrestleMania. The US Express regained the belts in June 1985, but lost them two months later to Brutus Beefcake and Greg Valentine. Windham left the WWF soon after, and Rotunda was teamed with "Golden Boy" Dan Spivey as "The American Express", who had limited success in 1986.
In the WWF, Rotundo became Irwin R. Schyster (I.R.S.) and he is perhaps best known for this role. Irwin R Schyster was a heel "tax-man" gimmick (he was portrayed as a former IRS tax collector from Washington, D.C.) who harassed all of the faces and fans, urging them to pay their taxes. He was, however, a sound technician in the ring - this would later see him form the team of "Money Inc." with Ted DiBiase and together the two men won the WWF World Tag Team Championship a further three times. Money Inc.'s first title reign was at the expense of the Road Warriors (using the name "the Legion of Doom" in their WWF stint), making Rotunda the only tag team wrestler to defeat the Warriors twice for Tag Team titles.
After Money Inc. was disbanded due to Ted DiBiase retiring from wrestling on a performing basis, Rotundo went back to singles wrestling. Rotunda's biggest singles feud was with Razor Ramon. He also engaged in a feud with Tatanka, who he accused of failing to pay a gift tax on a sacred headdress. Rotunda would join Ted DiBiase's Million Dollar Corporation stable, going on to often team with fellow member Bam Bam Bigelow while trying to regain tag team gold. Rotunda later refocused again on singles wrestling, feuding with The Undertaker in a long rivalry, with both gaining momentum leading up to their clash at the 1995 Royal Rumble. This included I.R.S defeating many jobbers on Monday Night Raw, re-possessing graves, and also interfering in a Casket Match between The Undertaker and Yokozuna. When the two eventually squared off, the Undertaker was victorious following a chokeslam, but was thwarted when his urn was stolen after the match. Later in 1995, Rotunda suffered an injury at the hands of Lex Luger, which resulted in a shattered disc after being hit in the chin. During the healing process, Rotunda was given a role as an agent, but he again went to World Championship Wrestling to wrestle on a full time basis.
When returning to WCW, he reprised his role of Michael Wallstreet, wearing similar attire to that of Ted DiBiase. His persona and wrestling ability were almost the same as his previous I.R.S. character, stating in a pre-recorded debut promo on the first ever WCW Monday Nitro: "I'm sure that the I.R.S. is gonna be watching me real close." Rotunda failed to recapture his earlier success, despite changing his name to both VK Wallstreet (a play on Vincent Kennedy McMahon) and Mister Wallstreet. He joined the New World Order (nWo) briefly at the request of DiBiase after defeating Mike Enos on the December 9, 1996 edition of Nitro, and wrestled in All Japan Pro Wrestling and New Japan Pro Wrestling as a member of "nWo Japan". Despite his nWo involvement, he was kicked out of the group by J.J. Dillon on April 21, 1997 because his nWo contract was apparently invalid, but still declared himself to be "anti-WCW", participating as a jobber on WCW Saturday Night. In 1999 he reformed the Varsity Club with Kevin Sullivan, but it never reached the level of its prior success, partly due to nagging injuries on Rotunda's part, and was disbanded in early 2000.
Rotundo continued to wrestle primarily in Japan throughout the 1990s until he retired to run a security company with his wife in 2004.
Rotundo was rehired by WWE as a road agent in 2006, and has made face appearances (like some other retired wrestlers) as Irwin R. Schyster. One such appearance was on the August 6, 2007 edition of Monday Night Raw; Mr. McMahon was discussing his IRS troubles with The Coach, and when the conversation ended, Rotunda lowered the paper covering his face (The Financial Times) and revealed himself.
Rotundo appeared as I.R.S. on the December 10, 2007 15th Anniversary edition of Raw, winning a 15 man Battle Royal, only to be paid off by his former tag team partner Ted DiBiase to eliminate himself and give DiBiase the win.
On the March 10, 2008 episode of Raw, U.S. Express made an appearance in a rematch from WrestleMania I against Volkoff and The Iron Sheik. They were interrupted by diva Jillian Hall, who offered to sing "Born in the USA" for them; however, she was given an airplane spin by Rotundo.
Rotundo appeared in the segment, "Top Rope Theatre" on WWE.com on February 19, 2009 talking to Kelly Kelly. In this online storyline he is playing a heel character once again and his arch enemy is "Hacksaw" Jim Duggan.
Rotundo appeared as I.R.S. on the September 7, 2009 edition of "Raw," of which Bob Barker was the guest host. Rotundo was a contestant in a "pricing game" similar to the "One Bid" qualifying segment of The Price is Right along with Santino Marella, Jillian Hall, and Chris Jericho, and bid on a "Best of Smackdown" DVD. Rotundo bid $50.00 (including tax), but overbid as the DVD's actual retail price was $18.99. Chris Jericho won the pricing game with a bid of $1.00 (as erroneously proclaimed by Bob Barker). Rotundo was again one of the contestants during the second round of the pricing game as is the format of the "One Bid" segment. A.J. Pierzynski of the Chicago White Sox filled in the vacated spot Chris Jericho held. This time the bid was for a travel package to Wrestlemania XXVI in Glendale, Arizona. Rotundo bid $2,000.00 for the package. The actual retail price was $1,247.00, making Santino the winner after a bid of $1,200.00