He first gained national attention as a star at Robert G. Cole Junior-Senior High School in San Antonio, Texas. He became High School player of the year, sometime during his playing years there. As a young man, he attended Louisiana State University, where he first achieved international fame. At LSU he was a two-time first team All-American, two-time Southeastern Conference player of the year, and the national player of the year in 1991.

O'Neal plays in the 1995 NBA Finals for the Orlando Magic.He was chosen #1 overall by the Orlando Magic in the 1992 NBA Draft, and helped the team to a commendable 41 wins that year, missing the playoffs by a single game. He further raised his fame that year with two infamous dunks which broke the supports holding the basket and backboard, both on national television: the first coming against the Phoenix Suns, the second against the New Jersey Nets.

In the 1993-94 season, Shaq helped the Magic to their first playoff birth ever.
In 1994-1995, O'Neal and Anfernee (Penny) Hardaway helped their team reach the NBA Finals, but were swept in four games by the Houston Rockets.

After the 1995-1996 season, Shaq left Orlando to join the Lakers for an unprecedented seven year $120 million contract. He and teammate Kobe Bryant created one of the most effective guard-center combinations in NBA history.

O'Neal led the Los Angeles Lakers to three consecutive NBA titles (2000, 2001, 2002). He was named MVP of the NBA Finals all three times and has the highest scoring average for a center in Finals history. He was also voted the 1999-2000 regular season Most Valuable Player, almost becoming the first unanimous MVP in NBA history.

In 2004, O'Neal and Bryant saw public inflamation in their longstanding feud, perhaps causing their surprise NBA Finals loss to the Detroit Pistons. Following this, O'Neal sought a trade from the Los Angeles Lakers.

On July 14, Shaq was officially traded to the Miami Heat for Caron Butler, Lamar Odom, Brian Grant and a first-round draft pick. The trade was immediately considered one of the most important in sports history, with analysts uncertain that one man could replace so many of Miami's key players. However, Shaq's new-look Heat surpassed all expectations, easily claiming the best record in the Eastern Conference. Those he was traded for failed to even lead the Lakers to the playoffs. Many pundits compared the Lakers trade of Shaq to the Boston Red Sox trade of Babe Ruth, referring to their dismal following season as "The Curse of the Shaq-bino". He narrowly lost the 2004-2005 MVP award to Phoenix Suns guard Steve Nash in one of the closest votes in history. Despite being hobbled by a deep thigh bruise, Shaq lead the Heat to the Eastern Conference Finals and a Game 7 against the defending champion Detroit Pistons, but Detroit emerged victorious, 88-82 and advanced to the Finals.

O'Neal has been selected to the All-Star Game every year since his rookie season in 1993 (except for the 1999 lockout season, in which the game was not held).

He has also established himself as one of the league's best defenders, receiving All-NBA-Defensive honors in 2000, 2001 and 2003.

O'Neal was a key member of the 1994 World Championship and 1996 Olympic basketball team, which won gold.

He has been elected by the NBA as one of the "50 Greatest Basketballers" in 1996. He was the youngest member of this list.

In 2005, O'Neal became the first player in NBA history to average over 20 points and 10 rebounds per game for 13 seasons.

O`Neal has earned All-NBA-Team honors in 11 of his 13 seasons.

He also was awarded the MVP in the 1999-00 season and in the 2003-04 All-Star game.