On the court he was dominant the big man in the middle and somehow over nineteen years in the NBA Shaquille O'Neal kept up and off court profile to match acting. Wrapping full -- surprising all over... See More
On the court he was dominant the big man in the middle and somehow over nineteen years in the NBA Shaquille O'Neal kept up and off court profile to match acting. Wrapping full -- surprising all over above all entertaining now at 39 he's hung up his sneakers for good in the question is. What -- next act he tells ABC's Robin Roberts in tonight's Nightline in -- It's an impressive -- Shaquille O'Neal's mega mansion when the year. This modular room. Complete with a 40000 square foot gym it's a straight path. There are dozens of calls all -- old water red Ferrari. You have to -- that its is own private islands or as -- calls it uses your proposal. This is what nineteen seasons of pro basketball game. This year the 39 year old retired from the game that made him famous. And now he's betting that his second career. As a purveyor of all things Shaq could be just as successful. What. Isn't that athletes have. A tough time with that transition -- we seeing so many that make such a great salary and they go bankrupt years later. I don't know if you can doesn't think the mistake of all of this. I did -- -- younger became. Two variants. As you get older you're supposed to do was moved to come over there was Goldman. -- has always been something of a wise guy. But in the business since he became sandy after Magic Johnson gave him some priceless advice so many improvements and -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Some fall back -- Shaq took that advice to heart and instead of spending his money he began investing it in everything from his own shoe line. Took -- five guys burger chain. He's now valued at over 250. Million dollars. Any -- all by being humble admitting he doesn't always know -- all. -- been going on teamwork it's one thing I've been doing -- teaming up with great people rather than trying to -- Many murders -- -- -- -- and figure who would do. It's all about teamwork when it comes to -- And he's played with the -- LeBron. It did write a book that it won't when he wanted to kill -- recruit -- -- buffalo. Do you. The kid blows one time though earlier did new. Northern -- whose purpose and would descend to give them and only met a wonderful stuff we want to know before. So -- really matters. And while most robberies last a lifetime. It's a credit the shacks easygoing personality. That he's willing to let bygones be bygones. We -- you -- was nearly perfect. Moment from their influence over his missiles -- -- to adapt. He's had to adapt growing up a military brat. His family was constantly moving growing up with little themselves a simple thing like lunch from white council could be a banquet. But on one particular trip. That -- you know. The -- rule will work for who tomorrow gave him who. So when he doubled karma. -- more food -- -- you ever make it. If you have to help those in the -- be -- -- The ones in need right now are the workers affected by the NBA lockout the president -- the best -- we will be ashamed. And if rich people. Calls -- people to lose their jobs boom is gonna open the human controlled. He's been hired to work -- Commentator win and if the basketball season starts. But in the meantime he's spending his days with his girlfriend Nikki hoops Alexandra. A reality show contestants from flavor of loan. -- -- -- -- -- I was there really taught how to do their relationship no you know sort you can show them. We're -- and we both have a lot of past mistakes. We could -- -- off. It's those past mistakes that seemed to -- -- -- who -- in the picture Jack was married to Sean Nelson for almost seven years their marriage broke up amid rumors of infidelity. -- -- very earnest. -- will say -- and saying that you were a man who had options. At that time being in that world is from thing I can explain it on camera -- my command room questions have room for commemorative Jordan Rich couple. Give of the medical. And what used to be a full house with a wife and kids. Is now just in his girlfriend an unexpected turn for sure -- -- through periods. The life for Shaq has been full of surprises. And for the rest of us well Shaq has one last surprise. Always a big believer in education Shaq is well on his way to earning his Ph.D. Once argued that vigorous. Pruning from. -- -- funeral home or check meant. Well not message certainly more don't -- -- seriously. Notes will love you and everybody else want to address this such check when loneliness. For example -- -- Check doctor O'Neill you -- know you don't think you'll not soon enough but you -- yeah. The effect of it and even though F. Scott Fitzgerald said that American lives don't have second acts. He mostly forgotten about overtime. Well I'm Robin Roberts for Nightline. Special guy -- new book. Shaq on cut my story went on sale today thanks to Robin Roberts for that interview.
This transcript has been automatically generated and may not be 100% accurate.