Kerr was born in Beirut, Lebanon to Malcolm H. Kerr, an American academic who specialized in the Middle East, and his wife, Ann (Zwicker). He has three siblings. His grandfather, Stanley Kerr, volunteered with the Near East Relief after the Armenian Genocide and rescued women and orphans in Aleppo and Marash before eventually settling in Beirut. Kerr spent much of his childhood in Lebanon and other Middle Eastern countries. While in Beirut in the summer of 1983, he met a number of US Marines who were later killed in the Beirut barracks bombings. Kerr attended Cairo American College in Egypt, the American Community School in Beirut, Lebanon, and Palisades High School (now Palisades Charter High School) in Los Angeles, graduating in 1983.

Malcolm Kerr was killed by members of the Shia Lebanese militia called Islamic Jihad on the morning of January 18, 1984 at the age of 52 while he was serving as president of the American University of Beirut. He was shot twice in the back of his head, by gunmen using suppressed handguns, in the hallway outside his office. Kerr was 18 years old at the time, and a college freshman; regarding his father’s death, he has said: “Before my father was killed, my life was impenetrable. Bad things happened to other people.” The Kerr family sued the Iranian government under the Antiterrorism and Effective Death Penalty Act of 1996. While warming up with the Arizona Wildcats for a game at arch-rival Arizona State in 1988, Kerr had to deal with many ASU Sun Devil fans in the crowd chanting “PLO” and “your father’s history.” Though tearful, Kerr led the Wildcats to victory, scoring 20 points in the first half, making all six of his three-point attempts. The athletic director of Arizona State, Charles Harris, sent a letter of apology to Kerr a few days later.

Kerr graduated from the University of Arizona in 1988 with a Bachelor of General Studies, with emphasis on history, sociology and English.

Minimally recruited out of high school, Kerr played basketball for the University of Arizona from 1983 to 1988. In the summer of 1986, Kerr was named to the USA Basketball team that competed in the FIBA World Championship in Spain. The team was the last American Men’s Senior Team composed strictly of amateur players to capture a gold medal. He blew out his knee in the tournament, usually a career-ending injury, forcing him to miss an entire season (1986–87) at Arizona. He helped the Wildcats reach the Final Four of the NCAA Division I basketball tournament in 1988 along with fellow All-American teammate Sean Elliott. Kerr also set an NCAA record for 3-point percentage in a season (114–199, 57.3%).

Kerr was selected by the Phoenix Suns in the second round of the 1988 NBA draft. He was traded to the Cleveland Cavaliers in 1989. He spent over three seasons (1989–1992) there and then part of the 1992–93 season with the Orlando Magic.

Kerr married Margot Kerr, his college sweetheart, in 1990. They have three children: Nick, Maddy and Matthew.

In 1993, he signed with the Chicago Bulls. The Bulls made the playoffs in the 1993–94 and 1994–95 seasons, but without Michael Jordan’s presence for all of 1994 and much of 1995, the team could not advance to the Finals. However, with Jordan back full-time for the 1995–96 season, the Bulls set a then NBA-record of 72–10 and defeated the Seattle SuperSonics in the 1996 NBA Finals.

Kerr played a major part of the Bulls’ championship victory in the 1997 NBA Finals against the Utah Jazz. In the final seconds of Game 6 with the score tied at 86, he took a pass from Jordan and hit the title-winner. The Bulls won, earning the franchise’s fifth title. Kerr also won the 3-Point Shootout at the 1997 All-Star Game.

In January 1999, Kerr was acquired by the San Antonio Spurs in a sign-and-trade deal with the Bulls, whereby Chuck Person and a first-round pick in the 2000 NBA draft was sent to Chicago. The Spurs reached 1999 NBA Finals and won their first NBA Championship with a 4–1 series victory over the New York Knicks. Kerr became the second player to win four straight NBA titles without being a part of the 1960s Boston Celtics dynasty, the other being Frank Saul, who won four straight with Rochester and Minneapolis from 1951 to 1954. Kerr and Saul were the only two players in NBA history to have won two championships with two different teams in consecutive seasons until Patrick McCaw achieved the same feat in 2019 and Danny Green in 2020.

Kerr was traded to the Portland Trail Blazers alongside Derek Anderson on July 24, 2001, in a deal that brought Steve Smith to the Spurs. He would remain in Portland for the 2001–02 season, playing in 65 games.

On August 2, 2002, Kerr was traded back to San Antonio along with Erick Barkley and a 2003 second-round pick. In return, the Trail Blazers received Charles Smith, Amal McCaskill, and Antonio Daniels. Kerr played in nearly every game (75) the following year, which was his final season in the league. In Game Six of the 2003 Western Conference Finals against the Dallas Mavericks, Kerr made four second-half three-pointers that helped eliminate Dallas. The Spurs eventually won the NBA championship by beating the New Jersey Nets in the 2003 NBA Finals, 4–2.

In 2003, Kerr became a broadcast analyst for Turner Network Television (TNT), offering commentary alongside analyst Marv Albert. During his tenure, he performed a segment sponsored by Coors Light called Steve’s Refreshing Thoughts in which he brought up interesting facts in NBA history. This segment continued through sponsorship, and became known as Steve Wonders, sponsored by Sprint. In the same time period, Kerr also contributed to Yahoo! as an NBA commentator.

On April 15, 2004, Kerr was announced as a member of a potential group of buyers that would acquire his old team, the Phoenix Suns, from Jerry Colangelo for $300 million. He became part of Suns management, acting as a consultant. During the 2006 NBA All-Star Weekend, he was a member of the San Antonio team that won the Shooting Stars Competition.

Kerr left broadcasting in 2007 to become general manager for the Phoenix Suns, but it was confirmed on June 28, 2010 that he would return as an NBA analyst for TNT starting with the 2010–11 NBA season. Since 2011, Kerr has also called the NCAA Men’s Division I Basketball Championship on Turner Sports and CBS, teaming up with lead broadcasters Jim Nantz and Clark Kellogg for the First Four and Final Four games, and with Albert in other rounds.

On June 2, 2007, Kerr announced that he would become the general manager of the Phoenix Suns beginning with the 2007–2008 season. In 2008, the Suns traded forward Shawn Marion and guard Marcus Banks to the Miami Heat in exchange for Shaquille O’Neal. The Suns were eliminated by the San Antonio Spurs in five games in the first round of the playoffs. On December 10, 2008, Kerr continued to remake the Suns roster by trading Boris Diaw, Raja Bell, and Sean Singletary to the Charlotte Bobcats in exchange for Jason Richardson, Jared Dudley, and the Bobcats’ 2010 second-round draft pick, which was used to draft Gani Lawal of Georgia Tech. On June 25, 2009, Kerr traded O’Neal to the Cleveland Cavaliers for Ben Wallace, Sasha Pavlovic, a future second-round draft pick and cash.

On May 5, 2010, the Suns wore their “Noche Latina” Los Suns jerseys in Game 2 against the Spurs to be united against the controversial Arizona immigration law. Kerr himself compared the law to Nazi Germany.

On June 15, 2010, Kerr stepped down as president and general manager of the Suns. He continued to own a one percent share of the Suns’ organization until 2014.

On May 14, 2014, Kerr reached an agreement to become the head coach for the Golden State Warriors, succeeding Mark Jackson. Kerr coached in the 2014 Summer League for the Warriors. During the 2014–15 season, the team’s offense employed elements of the triangle offense from his playing days in Chicago under Phil Jackson, the spacing and pace of Gregg Popovich in San Antonio, and the uptempo principles Mike D’Antoni and later Alvin Gentry used in Phoenix when Kerr was the GM.

After the Warriors beat the Houston Rockets to win their 14th consecutive game, Kerr became the first coach to start his career with a 19–2 record. This beat out Al Cervi and his 18–2 start with the Syracuse Nationals. On December 10, 2014, Kerr became the first NBA rookie head coach to win 21 of his first 23 games. He was named the head coach of the Western Conference team for the 2015 NBA All-Star Game after Golden State had the best record in the conference. On April 4, the Warriors beat the Dallas Mavericks 123–110 to clinch home-court advantage throughout the playoffs, and Kerr got his 63rd win of the season to become the highest winning rookie head coach in NBA history, passing Tom Thibodeau and his 62 wins with the Chicago Bulls in the 2010–11 season. In the NBA Coach of the Year voting, Kerr was runner-up to Mike Budenholzer.

Kerr was a regular contributor to the website Grantland from 2011 until it closed in 2015.

After the first two days of the defending champion Warriors’ training camp, Kerr took an indefinite leave of absence to rehabilitate his back, which had caused problems since the 2015 NBA Finals. Around this time, assistant coach Luke Walton assumed Kerr’s coaching duties. Kerr missed all of 2015 and most of January 2016, although technically the NBA credited Walton’s win-loss record to Kerr. Kerr said “I think it’s ridiculous”, when asked about getting all of Walton’s wins. On January 22, 2016, Kerr returned to coaching after missing 43 games, but warned he might need to miss games occasionally if there was a recurrence of the headaches and pain related to the spinal fluid leak that sidelined him. The Warriors went 39–4 with interim coach Luke Walton. The Warriors went 34-5 after Kerr returned to coaching. Golden State broke the 1995–96 Chicago Bulls 72–10 record by winning 73 games. Kerr became the first person in NBA history to be a part of 70-win teams as a player and head coach. He was named 2015–16 NBA Coach of the Year. Kerr would lead the Warriors to the 2016 NBA Finals where they would again face the Cleveland Cavaliers. The Warriors lost in seven games.

On November 20, 2016, the NBA announced that Kerr had been fined $25,000 for public criticism of officiating during a radio interview with KNBR 680 on November 17. Kerr missed time during the 2017 playoffs due to recurring back issues. Associate head coach Mike Brown has acted as acting head coach during periods of Kerr’s absence, and Brown continued head coaching into the playoffs leading the Warriors to a 12–0 record in the postseason. Kerr returned for the 2017 NBA Finals where he led the Warriors to victory over the Cleveland Cavaliers in five games. The Warriors finished the playoffs with a 16–1 record, the best postseason winning percentage in NBA history. Kerr is the fourth coach in NBA history to win two championships in his first three seasons of coaching. Kerr won his third championship as a head coach when the Warriors defeated the Cleveland Cavaliers in the 2018 NBA Finals in four games to give Kerr his eighth championship of his career.

On October 27, 2020, Kerr endorsed Joe Biden for President alongside 76ers coach Doc Rivers in a video with The Lincoln Project, citing the need to “stand for truth over lies” and to “reject white supremacy.”