On June 1, 1993, soon after Shaquille O’Neal finished his first NBA season, legendary LSU coach Dale Brown wrote a letter to his former All-American congratulating him on a great rookie campaign.

What’s more, Brown alerted O’Neal to the pressures of his newfound fame.

“Affect mankind,” one piece of the letter read. “Affect your fellow man, and always for the good. Shaquille, leave a legacy beyond trophies and statistics, because, and I hate to say this, but your time will also pass and the glory you enjoy will only be a memory.”

The 39-year-old O’Neal, who announced Wednesday via Twitter he’d played the last of his 19 pro seasons, will formally retire at noon Friday during a news conference at his Windermere, Fla., home.

Brown flew to Florida on Thursday to spend a couple of days celebrating with the man of the moment — and to tell him how proud he is.

“When they publish that he’s retiring, most of the stuff you’re going to read is of his statistics and championships and All-American honors,” Brown said. “That’s not the legacy he left. The legacy he left is being kind to the bellman, the reporter, the taxi cab driver, the down-and-outer, the little kids. He’s really good with that.”

Known off the court for his fun-loving nature, his assortment of silly nicknames and his five-star soundbites, O’Neal was a unique superstar who’s impact on American culture went beyond anything Brown ever imagined.

As a player, he won four NBA championships as a 15-time NBA All-Star, scored 28,596 points to rank fifth on the all-time scoring list and won the NBA MVP award in 2000.

SLAM magazine in February released a list of the 500 greatest players in NBA history. O’Neal ranked fourth behind Michael Jordan, Wilt Chamberlain and Bill Russell.

It all started at LSU, where O’Neal starred from 1989-92.

His alma mater announced plans last month to unveil a bronze statue of O’Neal, the 1991 National Player of the Year, outside of the Pete Maravich Assembly Center’s new practice facility.

“I knew he would be a star, but I did not dream that he would wind up being a mega-star,” said Brown, the LSU coach from 1972-97. “He improved every year from his freshman year on, and he just got better and better and better.”

Hampered by injuries in the final years of his career, O’Neal played in only 37 games for the Boston Celtics this past season. In his prime, he was an overpowering force.

Bob Starkey, who served as a Brown assistant during the O’Neal era and a Lady Tigers assistant for several years after that, said the 7-foot-1, 325-pounder’s longevity stood out as much as his rim-rattling dunks.

“When it comes time to step away from the game, nobody knows better than the athlete. Shaquille knows his body,” Starkey said. “I tell you what, that’s a long time to play when you’re a post player. That’s a lot of years of banging inside. He’s done a lot of great things playing, but I think the length of time he’s played at that position really stands out to me.”

Stanley Roberts agreed.

Roberts spent eight seasons as an NBA center after playing alongside O’Neal at LSU during the 1989-90 season.

“How many centers you know that survived 19 years in the NBA?” Roberts said. “He’s a great testament to big guys. People don’t realize, you carry a lot of weight. Your joints just weren’t designed to carry that kind of weight.”

O’Neal’s road to LSU began on a military base in Germany where his father, Sgt. Philip Harrison, was stationed.

Brown had finished giving a motivational speech to U.S. Army personnel. O’Neal cornered him to ask if the coach could teach him any weight-training exercises.

Brown peered up at O’Neal, then down at his size 17 shoes.

“How long have you been in the service, soldier?” Brown asked.

“I’m only 13 years old,” O’Neal told him.

Brown asked to speak with Harrison. O’Neal signed with Brown a few years later.

During his three seasons as an LSU star, O’Neal scored 1,941 points and grabbed 1,217 rebounds, but his magnetic personality was always as big as his game.

“He had a fake cell phone he carried everywhere,” Starkey said. “He had fake conversations with famous people — politicians, celebrities. It had a little button that would fake a ring. He’d take a call and hand you the phone.”

O’Neal, the No. 1 pick of the 1992 NBA draft, left LSU after his junior year. He returned in 2000 to receive his diploma, mixing correspondence courses with pro basketball.

Starkey said O’Neal never stopped bleeding purple and gold.

When the Lady Tigers arrived in Indianapolis for the 2005 Final Four, O’Neal showed up at their hotel to say hello. The next night, he provided tickets for the entire team to watch a Heat-Pacers game.

“As far removed as he is from this university, he absolutely loves LSU,” Starkey said. “I hear stories all the time where he’ll be in the airport or a mall and see somebody with an LSU hat or an LSU sweatshirt, and he’ll make his way over and introduce himself. He’ll say, ‘I went to LSU, too.’”

Roberts suspects O’Neal, who is working toward a PhD from Barry University in human resource development, will not get bored outside of those giant sneakers he’s worn for nearly two decades.

“I think he’ll be as successful in his next career as he was in the NBA,” Roberts said. “He’s the kind of guy, he’s not going to stop. He’s not going to sit still and retire and go gracefully into the night. That is not going to happen.”

Brown keeps a copy of the letter he wrote O’Neal when the former LSU standout’s road to stardom began.

He knows as O’Neal enters the next phase of his life, he will continue to make his old coach proud.

“Many people leave and they’re not prepared for anything else,” Brown said. “He’ll have his doctrine. He can act. He could run for sheriff. He could run for mayor. He’s a U.S. Deputy Marshal. He’s just a very diversified. Plus, he’s the most benevolent athlete I know.”