After a playing career at Concordia College and Moorhead State, Joerger joined the Dakota Wizards of the International Basketball Association as the team's general manager. He became the team's assistant coach in 1997 and eventually took over as the head coach for the 2000–01 IBA season. Joerger had immediate success as a head coach, leading his team to a 30–10 regular season record. After being down 0–2 in the IBA Finals best-of-5 series, the Wizards came back to defeat the Des Moines Dragons 3–2, winning their first championship.
Joerger remained with the Wizards as IBA, IBL, and CBA teams merged to create the new Continental Basketball Association after the league declared bankruptcy under the ownership of Isiah Thomas. As a former IBA team, the Wizards were declared "lower-tier" in the 2001–02 season and were given a shorter schedule with two other former IBA teams and an expansion team to make up the National Conference. With Joerger at the helm, the Wizards finished with a league-leading 26–14 record. For his success, Joerger was named the CBA Coach of the Year. After sweeping the Fargo-Moorhead Beez 3–0 in the conference finals, Joerger won his first CBA championship as his team defeated the Rockford Lightning 116–109 in a winner-take-all championship game. Joerger continued to have success with the Wizards in the CBA, reaching the conference finals with a league-leading 31–17 regular season record in 2002–03 before losing to the Yakima Sun Kings 3–1. Throughout the 2003–04 season, Joerger lost six players to NBA call-ups, which included Sean Lampley, Oliver Miller, Kaniel Dickens, Maurice Carter, Eddie Gill, and Rodney Buford. Despite losing talent, Joerger still managed to coach his team to a league-best 34–14 regular season record, and was again named the CBA Coach of the Year. With Dickens and Carter back from the NBA, the Wizards defeated the Rockford Lightning 3–1 in the semi-finals and won their second CBA championship with a 132–129 victory over the Idaho Stampede. Following another championship season and a stint with the USBL's Cedar Rapids River Raiders, Joerger left the Wizards for an opportunity to coach the Sioux Falls Skyforce. With the Skyforce, a franchise that had missed the play-offs the past few seasons, Joerger had immediate success, guiding them to a 31–17 record and faced off against his former assistant, Casey Owens, and the Dakota Wizards in the conference finals. In 5 games, the Skyforce came out on top and went on to defeat the Rockford Lightning 3–1 for the 2004–05 CBA championship. In the 2005–06 season, despite going 2–0 in a round-robin playoff format based on quarter point percentage, Joerger missed out on just his second championship as a head coach after a 30–18 regular season.
CBA to D-League
In April 2006, the Skyforce, the Wizards, and the Idaho Stampede made the jump from the CBA to the NBA Development League. In May, Joerger left the Skyforce and returned to the Wizards as the head coach once again. As expected, Joerger had immediate success in the D-League, guiding the Wizards to a league-best 33–17 record. After a first round bye, Joerger's team knocked off the Skyforce 115–113 in a one-and-done semi-final and went on to defeat the Colorado 14ers 129–121 in a classic overtime championship game.
NBA
Memphis Grizzlies
With five minor league championships under his belt, the National Basketball Association finally took notice and Joerger was hired by the Memphis Grizzlies as an assistant coach for the 2007–08 season under head coach Marc Iavaroni. In 2011, under Lionel Hollins, Joerger was promoted to lead assistant and took over as the team's defense specialist. The Grizzlies improved in defensive efficiency from 24th overall in 2010 to 9th in 2011, 7th in 2012, and 2nd in 2013. On June 10, 2013, the Grizzlies organization announced that Lionel Hollins would not be returning as the team's head coach, despite reaching the conference finals for the first time in franchise history. On June 27, 2013, Joerger was hired as the Grizzlies' head coach for the 2013–14 season. In his first year, Joerger was named the Western Conference Coach of the Month in both January and April. On May 28, 2014, it was announced that Joerger was signed to a 3-year contract extension. On May 7, 2016, Joerger was fired by the Grizzlies after three seasons as the team's head coach.
Sacramento Kings
On May 9, 2016, just two days after being fired by the Grizzlies, Joerger signed with the Sacramento Kings to become their head coach. On April 11, 2019, the Kings fired Joerger after the team failed to reach the playoffs in three seasons under Joerger; in his last season as coach, the Kings had their best record since they last reached the playoffs in the 2005-06 season.
