He is the team president and chief executive officer (CEO) for the Chicago Bears of the National Football League (NFL).

He began his NFL front office career with the St. Louis Rams in 1997, and was an executive of the organization when it won Super Bowl XXXIV in 2000.

In 2015, Warren became the first African-American chief operating officer (COO) of an NFL team, during the time he worked for the Minnesota Vikings.

[20] While at the firm, Warren worked with former Southeastern Conference Commissioner, Michael Slive,[21] and collegiate sports attorney Mike Glazier on many high-profile cases.

[30] Vermeil praised Warren in 2012 as being "as critical and important a part of [the] Rams Super Bowl Championship team as anybody in [the] organization.

"[15] In 2001, Warren joined the Detroit Lions as the senior vice president of business operations and general counsel.

[31] Following his time with the Lions, Warren returned to Phoenix where he worked for the international law firm Greenberg Traurig.

The Vikings then hired Warren as their executive vice president of legal affairs and chief administrative officer in 2005.

He restructured the management of the organization, which included creating new senior leadership positions, overseeing administration and finance, human resources, legal, marketing and fan engagement, and sales and corporate sponsorships.

[44][45] Warren was also responsible for overseeing construction of the Vikings' new practice facility in Eagan, Twin Cities Orthopedic Performance Center, which opened in March 2018.

The ribbon-cutting ceremony was held in June 2018 with attendees including NFL Commissioner Roger Goodell, Twin Cities Orthopedics CEO Troy Simonson, and Governor Mark Dayton.

The facility is only the first phase in a planned 200-acre development which is expected to include offices, retail, residential, hospitality, and a conference center.

Under Warren's oversight, the Big Ten persevered through the COVID-19 pandemic and he expanded the conference with the future additions of USC and UCLA starting with the 2024 season, with Washington and Oregon later following suit after his tenure as Commissioner ended.

[50][51][52] Not long after USC and UCLA's announcement that they would be joining the conference, he oversaw the Big Ten's signing of a new seven-year media rights deal with NBC, Fox, and CBS, estimated to be worth at least $7 billion.

[57] In 2017, on the eve of Super Bowl LI, Warren was presented with the inaugural Texas Southern University Pioneer Award.

[60] In December 2019, Warren was featured on the cover of Sports Business Journal alongside Serena Williams, LeBron James, and Adam Silver where he received the honor of "Best Hire" of the year.

[65] In March 2016, Warren was appointed by University of Minnesota President Eric W. Kaler to serve as a member of the selection committee for the role of athletic director.

[73] Warren and his wife Greta have also "adopted" Lucy Craft Laney Community School in Minneapolis, Minnesota.

[74] For each of the past 5 years, the Warrens have donated thousands of backpacks filled with school supplies to the student body.