Dan Rooney, the longtime Pittsburgh Steelers owner who led the NFL’s diversity efforts for decades, died on Thursday, the team announced.

He was 84.

Rooney’s first job with the Steelers, a team his family has controlled since 1933, was as a water boy at age 12 and he began working in the front office after he graduated from Duquesne University in 1955. He eventually served as general manager and ran the day-to-day operations of the club from 1975 though 2003 when Dan Rooney’s son, Art Rooney Jr., took over those duties.

The Rooneys and the Maras, which have controlled the New York Giants since 1925, are considered the first families of the NFL, it wasn’t until the NFL-AFL merger announced in 1966 that the Steelers became a powerhouse.

The Steelers shifted to the American Football Conference in 1970, the same season the franchise began play at Three River Rivers Stadium, and Pittsburgh became the most dominant team of the decade led by the likes of Terry Bradshaw, Jack Ham, Franco Harris and head coach Chuck Noll. The team won six consecutive AFC Central titles to close out the decade, a run that included three Super Bowl titles.

“It was an amazing phenomenon,” NFL Commissioner Roger Goodell wrote in the preface to Rooney’s 2008 autobiography - the region’s passion for football, the way the Steelers united the community and the love and the respc the fans had for Art, Dan and the rest of the Rooney family. It was clear it was very special.”

In his later years, Rooney became best known for the NFL’s effort to make the league’s coaching ranks more diverse and his appointment as ambassador of Irelend by President Obama.

The "Rooney Rule," created in 2003, required teams to interview minorities for head coaching vacancies and senior football operations jobs. The rule was expanded in 2016 to include women for executive openings.

"In the past, we've had some that were just token interviews," Rooney told USA TODAY Sports in May 2013. "They talked to someone on their staff for two minutes and said, 'OK.' This hasn't been happening now. So I don't think you can get all excited over (backlash from) one year."

Seventeen minority head coaches were hired from 2003 through 2017, more than double the number that had been hired since the NFL’s founding in 1920.

Rooney, a supporter of President Obama’s 2008 presidential campaign, was appointed as the ambassador to Ireland in 2009 and held the post until 2012. Rooney had long been a supporter of Ireland, raising millions to support cultural and education efforts in the country.

Rooney’s father, Art Rooney Sr., purchased the Steelers in 1933, a year after Dan Rooney’s birth with, urban legend has it, with $2,500 in racetrack winnings. The Rooney family has long had business interests in horse and dog tracks, which led the Steelers to restructure its ownership structure to comply with NFL anti-gambling rules.

Rooney was elected to the Pro Football Hall of Fame in 2010.

UPDATE: Pro Football Hall of Fame President & CEO David Baker released a statement about the passing of Dan Rooney:

“The Pro Football of Fame family mourns the loss of an incredible and loving man. Ambassador Rooney epitomized all that is GREAT about this game that he and his family helped grow into an American institution. His impact on the game was profound.

I have never met a man who possessed such humility and integrity as Dan Rooney. All of us associated with the Hall of Fame are indebted to him for the contributions he made to the game and for his decades of service as a member of our Board of Trustees.

Tomorrow, the flag at the Pro Football Hall of Fame will fly at half-staff in honor of one of the greatest men to ever serve this game. We will keep his wife Pat and the entire Rooney family in our prayers and hope they find comfort in knowing that Dan’s legacy will forever be kept alive in Canton, Ohio.”

Also, NFL Commissioner Roger Goodell added: “Few men have contributed as much to the National Football League as Dan Rooney, A member of the Pro Football Hall of Fame, he was one of the finest men in the history of our game and it was a privilege to work alongside him for so many years.  Dan’s dedication to the game, to the players and coaches, to his beloved Pittsburgh, and to Steelers fans everywhere was unparalleled."

Cleveland Browns owners Jimmy and Dee Haslam also released a statement:

"We are deeply saddened by the loss of Dan Rooney. Mr. Rooney was a great man and true leader who always put others before himself. His immeasurable impact on the NFL will forever be recognized and his legacy, which includes the Rooney Rule, will continue to guide our league. Mr. Rooney's dedication to the NFL is only surpassed by his commitment to his family. It was a privilege and we were extremely fortunate to have spent time with the Steelers and to be in the presence of such a world class person like Dan Rooney. We are graciously thankful for Mr. Rooney, the way he treated everyone he encountered and his passion for the NFL. Our hearts are with the entire Rooney family, who we know will miss him dearly, as will we, along with the entire NFL community.”