He played college basketball for the Marshall Thundering Herd before being selected in the second round by the Sacramento Kings in the 2010 NBA draft.

[6] Whiteside chose Marshall over UNC Charlotte, South Carolina, Kentucky, Auburn, and Mississippi State.

[7] Whiteside came to Marshall University under the radar during the start of the 2009–10 season, but it did not take long for him to make national attention.

He was spotlighted in the edition of December 28 of ESPN The Magazine's College Basketball column after he amassed 14 points, 17 rebounds and nine blocked shots over 29 minutes in a 60–53 win over the Ohio University Bobcats on November 28.

[8] A few weeks later on December 12, Whiteside recorded the Thundering Herd's first triple-double in a 105–54 rout of the Brescia Bearcats, scoring 17 points, grabbing 14 rebounds and blocking 11 shots.

The 182 blocks were also a national record for a freshman in a single season, topping 177 by BYU's Shawn Bradley in 1990–91.

[15] He spent time with the Kings' D-League affiliate, the Reno Bighorns, between November 29 and January 9,[16] before being ruled out for four to six months on March 4 after undergoing surgery to repair a partially torn patellar tendon in his left knee.

[24] After three games for Amchit in early May, Whiteside left Lebanon and joined the Chinese NBL team Sichuan Blue Whales.

[41] On January 11, 2015, Whiteside recorded a then career-high 23 points, 16 rebounds, 2 steals and 2 blocks in a 104–90 win against the Los Angeles Clippers.

[55] On January 15, 2016, Whiteside recorded his third career triple-double with 19 points, 17 rebounds and 11 blocked shots in a 98–95 win over the Denver Nuggets.

He returned to action on February 3, recording 10 points, nine rebounds and five blocks in 17 minutes off the bench in a 93–90 win over the Dallas Mavericks.

[57] Two days later, he recorded his third triple-double of the season and fourth of his career with 10 points, 10 rebounds and 10 blocked shots in 27 minutes off the bench in a 98–95 win over the Charlotte Hornets.

Whiteside finished as the league's leading shot-blocker in 2015–16, and he earned selection to the NBA All-Defensive Second Team.

In the first round of the playoffs, the Heat faced the sixth-seeded Charlotte Hornets, and in a Game 1 win on April 17, Whiteside made his postseason debut with 21 points and 11 rebounds.

[65][66] Whiteside became the first player in NBA history to go from a league minimum salary to a max level contract.

[67] In the Heat's season opener on October 26, Whiteside recorded 18 points, 14 rebounds and four blocked shots in a 108–96 win over the Orlando Magic.

[68] On October 30, he tied his career high with 27 points and grabbed 15 rebounds in a 106–99 loss to the San Antonio Spurs.

[72] On November 21, in a loss to the Philadelphia 76ers, Whiteside set a career high with 32 points while reaching double digits in rebounds for the 13th consecutive game to start the season.

[73] On December 14, he recorded 26 points and 22 rebounds in a 95–89 win over the Indiana Pacers, marking his fourth career 20–20 game.

[84] On November 1, 2017, he returned from a five-game absence with a bruised knee and scored 13 points and grabbed 14 rebounds in a 97–91 win over the Chicago Bulls.

[85] On December 26, 2017, he returned from an 11-game absence with a bone bruise in his left knee and had seven points and eight rebounds in 18 minutes in a 107–89 win over the Orlando Magic.

[88] On October 29, 2018, Whiteside had an NBA season-high 24 rebounds to go with 16 points and five blocked shots in a 123–113 loss to the Sacramento Kings.

[89] On November 7, he had 29 points, 20 rebounds and an NBA season-high nine blocked shots in a 95–88 win over the San Antonio Spurs.

[103] Nassan's Place provides low to moderate income families the opportunity to receive quality and affordable care for their children in a safe and carefree environment.

This news came to light during an April 10, 2019 indictment of Avenatti by a federal grand jury in Santa Ana, California.

"We entered into a mutually agreed upon settlement more than two years ago following the end of our relationship; a settlement that reflected Alexis' investment of time and support over a number of years as Hassan pursued a career in the NBA," Whiteside and Gardner told The Los Angeles Times in a statement released by his agent.