Steelers chairman Dan Rooney dies at 84

— -- Pittsburgh Steelers?chairman Dan Rooney, one of the NFL's most influential and popular executives, has died. He was 84.

A Steelers spokesman confirmed that Rooney died Thursday. No further details were immediately available.

Rooney took over operation of the team in the 1960s from his father, Art, who founded the franchise. From there, Dan Rooney oversaw NFL championships for a team that had never before played in an NFL title game.

"Few men have contributed as much to the National Football League as Dan Rooney," commissioner Roger Goodell said in a statement. "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. He was a role model and trusted colleague to commissioners since Bert Bell, countless NFL owners, and so many others in and out of the NFL.

"A voice of reason on a wide range of topics, including diversity and labor relations, Dan always had the league's best interests at heart. For my part, Dan's friendship and counsel were both inspiring and irreplaceable. My heart goes out to Patricia, Art, and the entire Rooney family on the loss of this extraordinary man."

Under Rooney's direction, the Steelers won four championships in six years -- Super Bowls IX, X, XIII and XIV. He also played a large role in assembling the 1974 draft class, considered the greatest class in NFL history, in which the Steelers picked four future Hall of Famers -- Lynn Swann, Jack Lambert, John Stallworth and Mike Webster.

Among his lasting accomplishments was his role in the establishment of the Rooney Rule, which was created in 2003 and requires teams to interview minority candidates for head coaching and senior football operation positions. The rule was named in honor of Rooney, who had served as chairman of the league's diversity committee.

Steelers star wide receiver Antonio Brown said in an Instagram post that Rooney was "one of the most genuine, and humble human beings I've had the pleasure of knowing."

Off the field, Rooney was appointed U.S. ambassador to Ireland in 2009 by President Barack Obama and served until his resignation in 2012. In March 2016, the Jackie Robinson Foundation honored Rooney with its Lifetime Achievement Award.

Rooney was born July 20, 1932, in Pittsburgh, to Art Rooney Sr., who founded the Steelers the following year. Dan Rooney played football for North Catholic High School and was named to the 1949 all-Catholic League second team, notably losing the first team spot to quarterback Johnny Unitas -- whom the Steelers later signed, and cut.

Rooney began working for his father in 1955 after graduating from Duquesne University. He was named president of the Steelers in 1975 and held that position until 2003, when he took on the role of chairman and his son, Art Rooney II, took over the presidency.

Dan Rooney, who was inducted into the Pro Football Hall of Fame in 2000, garners respect throughout the Steelers organization, from players to coaches to scouts. Key Steelers players routinely reference Rooney's impact on the team.

"I have played with guys that have come from other teams. They look shocked when they see our owners, whether it's Mr. Dan Rooney or Mr. Art Rooney II, walking around the locker room and walking around practice," Steelers quarterback Ben Roethlisberger said in January. "They don't ever see their owners. We see our owners every single day. I think it's just a blessing to know that they care about us, and that's one of the reasons we want to go win."

Former Steelers coach Bill Cowher, currently an NFL analyst with CBS, paid tribute to Dan Rooney with a tweet Thursday.

Rooney remained a fixture in the Steelers facility over the last few years. He had an affinity for St. Vincent College, which has hosted 51 training camps for the Steelers.

ESPN's Jeremy Fowler and The Associated Press contributed to this report.