Wagner graduated from Villanova University in 1992 with a Bachelor of Science in Accounting. He later graduated Beta Gamma Sigma from Columbia Business School in 1999.[3][5]
In 2008, he co-founded Knighthead Capital Management LLC alongside Ara Cohen.[3][6] The company is an investment firm that specialises in "fundamental analysis, operational and financial turnarounds and risk management".[7]
On 13 July 2023, Shelby Companies Limited (SCL), a subsidiary of Knighthead, became co-owners of association football club Birmingham City.[4] SCL currently own 96.64% of the EFL Championship side.[8] As a result of the takeover, Wagner became the club's chairman.[8] A month later, on 3 August 2023, former NFL player Tom Brady "entered a partnership" with SCL as a minority owner of Birmingham City.[9]
Since the takeover, plans to replace the club's current home of St Andrew's have been in the works. On 9 April 2024, SCL acquired a plot of land in Bordesley Green to use for a new stadium.[10][11] The proposed New Birmingham City Stadium will host 62,000 spectators and be surrounded by a "Sports Quarter", which will be used by all of the club's teams.[12][13] The project has an optimistic completion date of 2029.[14]
Despite relegation from the EFL Championship in Wagner's first season at Birmingham City,[15] the club was promoted straight back up as champions of EFL League One the following year.[16]
In May 2023, Wagner and retired quarterback, Tom Brady, entered into an agreement to purchase 10 percent of the Las Vegas Raiders from majority owner Mark Davis.[17] The original deal was delayed due to concerns from NFL owners that Brady and Wagner were receiving too big a discount.[18][19] In October 2024, a revised agreement was approved by NFL owners, with Wagner and Brady purchasing a five percent stake in ownership for a total of $220 million.[17][20]