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Kyrie Irving had just sunk into his chair next to Gordon Hayward, the new faces of the Celtics, at their introductory news conference Friday morning at TD Garden. Irving’s blank expression stretched to a wide grin as he was handed his green No. 11 jersey, the same number he wore in high school.

For the ensuing half-hour, Irving and Hayward laughed, reminisced, and looked forward to the upcoming season.

Team owner Wyc Grousbeck called Friday’s news conference a “historic and proud moment in Celtics history.’’ Irving heaped praise on coach Brad Stevens and the “illustrious’’ organization that sent two of its top players, a complementary piece, and two draft picks to Cleveland for Irving.

“When you have the unique opportunity of having special people and being a part of an organization like this, they do everything possible in order to put themselves out there to make such a great thing happen, you are just appreciative, and I’m grateful,’’ Irving said.

Irving rewound to the “roller coaster wave of emotions’’ that hit him after losing his second NBA Finals in three years with the Cavaliers. He had decided he wanted a change, a pronouncement that brought some public derision.

People questioned why he wanted to leave Cleveland, where he molded himself into a perennial All-Star, became part of one of the most lethal duos in the league with LeBron James, and solidified his local legend by sinking one of the most famous shots in NBA history to secure the franchise’s first championship in 2016.

Irving remained quiet and “patiently waited’’ once news surfaced that he wanted out of Cleveland.

More than three weeks later, the Celtics agreed to trade Isaiah Thomas, Jae Crowder, Ante Zizic, and an unprotected 2018 first-round pick via the Nets to the Cavs for Irving. Thomas’s hip injury prolonged the process, until the Celtics included an additional 2020 second-round pick from the Heat. Eventually, the Cavs were convinced, and trade was solidified.

“When Boston came knocking, I was answering,’’ Irving said. “It was pretty awesome the way it all transpired.’’

Irving was told the news as he filmed his movie, “Uncle Drew,’’ in Atlanta. After he received the call, he said, he removed himself from the situation and just watched cars pass by.

“I took in that moment because it really meant something, and it was the start of something anew,’’ Irving said.

Seemingly overlooked in the chaos surrounding Irving was Hayward, Boston’s first marquee acquisition of the summer.

Back in early July, he left the Utah Jazz as a free agent to sign with the Celtics. Thomas, a two-time All-Star, helped persuade Hayward to choose Boston, praising the quality of the organization and the top-notch sports city.

“He was somebody I was definitely excited about playing with,’’ Hayward said. “I have been in this business long enough to know it is a business. Things happen, things can change.

“I go from an opportunity of playing with IT and the rest of the guys who were on to now playing with Kyrie Irving, who is unbelievable, one of the best basketball players in the league. Another great opportunity for me.’’

Three seats away from Hayward sat a man who has been one of the most influential people in his life.

Hayward’s move to Boston means a reunion with Stevens. Together, they elevated Butler from a good mid-major program to a national force, bringing the program to its first national championship game in 2010.

Hayward started appearing on NBA radar, a prospect that seemed unlikely until he met Stevens, who was hired by the Celtics in July of 2013.

“I always had a dream to play in the NBA, but he was the first person, I think, who made me realize I could maybe get there one day,’’ Hayward said. “To be back and reunited with him, I am beyond excited, and I can’t wait to get to work.’’

Hayward said he and Stevens have come a long way since their 5:45 a.m. workouts at Brownburg High School, Hayward’s alma mater in Indiana.

“He couldn’t even grow a beard the last time I saw him,’’ Stevens quipped.

Pause.

“Can you?’’ Grousbeck responded, causing a roar of laughter.

The news conference ended after about 30 minutes. Irving stood up, jersey in hand, and looked at his father, Drederick Irving, whom Danny Ainge had called a “Boston University legend’’ earlier.

“Come on, Dad,’’ Irving mouthed. “This is your jersey.’’

Drederick wore the same number when he played at BU from 1984-88, leaving the program as its all-time leading scorer.

Father and son eventually met through a crowd of reporters, and the two hugged for several seconds. It was a fitting scene to conclude a news conference filled with apparent joy from all sides.

Earlier, Irving said playing in Boston was “meant to be.’’ Hayward joked it was destiny for them to play on the same team because they share the same birthday (March 23).

“It’s about to be crazy, G,’’ Irving said to Hayward.

Brad Almquist can be reached at brad.almquist@globe.com. Follow him on Twitter at @bquist13.