BOSTON – He was a prolific producer of rebounds and record albums. And nicknames, too, as if at 7-foot-1 and 350 pounds he was too big for the simple “Shaq” that made him an instantly recognizable, one-name star in all his endeavors.

Shaquille O’Neal had more than 28,000 points and almost 4 million Twitter followers. He appeared in six NBA finals, three times as the MVP, and seven feature films, twice in a starring role.

A 15-time All-Star, four-time champion and the 2000 NBA Most Valuable Player, the 39-year-old O’Neal announced his retirement on Twitter on Wednesday after spending most of his 19th season on the Boston Celtics’ bench, in street clothes because of leg injuries.

With a tweet saying, “im retiring,” O’Neal included a link to a 16-second video of him saying, “We did it; 19 years, baby. Thank you very much. That’s why I’m telling you first: I’m about to retire. Love you. Talk to you soon.”

An inveterate prankster who gave himself a new nickname — or several — in each of his six NBA cities, O’Neal didn’t notify his latest team, leaving it wondering about his plans. He played just 37 games this season, the first of a two-year deal at the veteran’s minimum salary, making just three brief appearances after Feb. 1.

“He’s a giant,” Commissioner David Stern said Wednesday at the NBA finals in Miami. “He’s physically imposing; he has an imposing smile. In the game he imposed his will, and he has done it for quite a long time. It’s been a great run here, and we’re going to miss him greatly. We hope we can find ways to keep him involved in the game.”

O’Neal retires fifth all time with 28,596 points, 12th with 13,099 rebounds, and a .582 field-goal percentage that is second only to Artis Gilmore among players with more than 2,000 baskets. His free-throw percentage of .527 — well, now is not the time to dwell on that.

“I’m a little bit sad,” said Pat Riley, the Heat president who also coached O’Neal when he won a title in Miami, and watched Kareem Abdul-Jabbar, Patrick Ewing and Alonzo Mourning when they retired. “It’s been an honor to be part of coaching great, great players. And he’ll go down as one of the greatest.”

Also one of the most charismatic players in NBA history, O’Neal was a franchise-saver when the Orlando Magic made him the No. 1 pick in the 1992 draft. He took them from the lottery to the playoffs in two years, then led them to the NBA finals in his third year before they were swept by Houston.

O’Neal signed with the Los Angeles Lakers in 1996 and had his greatest success there, winning three titles alongside Kobe Bryant and Coach Phil Jackson. But amid tension between O’Neal and Bryant after a loss to the Detroit Pistons in the finals, O’Neal was traded to the Heat in the summer of 2004.

After 31/2 years in Miami, a tenure that included his fourth NBA championship, O’Neal became a veteran for hire, moving to Phoenix, then Cleveland, and finally Boston. But he couldn’t deliver another title for Steve Nash and Amar’e Stoudemire with the Suns, with LeBron James with the Cavaliers, or with the Celtics’ Big Three of Kevin Garnett, Paul Pierce and Ray Allen.

At each stop he endeared himself to the fans and his new teammates with his effervescent smile and playful attitude, including the habit of adopting a new nickname he felt embodied his role with his new team. In Phoenix he was the “Big Shaqtus”; in Boston, the “Big Shamroq.”

“What a career for Shaq Diesel!!” James wrote on Twitter. “The most dominating force to ever play the game. Great person to be around as well. Comedy all the time!!”

O’Neal embraced social networking, amassing more than 3.8 million followers on his Twitter account and keeping them informed on his “random acts of Shaqness” — like sitting in Harvard Square, pretending to be a statue, or going out in drag on Halloween.

But O’Neal’s off-court persona couldn’t disguise the fact he was getting old.

“I’m glad that he retired. I think it was time,” former guard Tim Hardaway said. “He was hurting his legacy. You don’t want to see anybody hurt their legacy when they’re going out. I think a lot of people are happy he didn’t go through that pain of waiting too long. And I think it was tough for everyone to watch Shaq when he was playing hurt like that.”