Moncrief, Marvin Delph of Conway, Arkansas, and Ron Brewer of Fort Smith, Arkansas ("The Triplets"), along with head coach Eddie Sutton and assistant coach Gene Keady, resurrected the University of Arkansas basketball program in the 1970s from decades of modest success and disinterest, and helped lay the foundation for what became one of the country's premier college basketball programs through the mid-1990s. The Triplets lead the Razorbacks to the SWC championship, and a Final Four appearance in 1978. Moncrief's leadership on the court and electrifying play renewed interest in the Razorback program, and ushered in the winning tradition in the Arkansas basketball program. His jersey was retired not long after he graduated from school and went on to the NBA, and is one of only two, along with Corliss Williamson. Moncrief was the school's all-time leading scorer until Todd Day broke his record in 1992. On Nov. 10, 2014 Moncrief was inducted into the Southwest Conference Hall of Fame. On Feb 7, 2015 Moncrief was honored by Arkansas when his name was put on a banner that was hung in Bud Walton Arena.
Although Jerry West wanted to draft him to the Los Angeles Lakers, Moncrief's NBA career started with the Milwaukee Bucks in 1979 when he was drafted 5th overall. Moncrief spent the next ten seasons with the Bucks. In Game 3 of the first round of the 1982 NBA Playoffs, Moncrief made a running bank shot at the buzzer to beat the Philadelphia 76ers. After sitting out of the NBA for one year, Moncrief played one season with the Atlanta Hawks before retiring. The Bucks retired his no. 4 jersey in 1990, and rededicated it at halftime on January 19, 2008, when the Warriors, with whom he was a shooting coach, visited the Bradley Center in Milwaukee, Wisconsin to play the Bucks.
During the 1980s, Moncrief was the leader of the Milwaukee Bucks, who had the third best winning percentage for the decade behind only the Los Angeles Lakers and Boston Celtics. Moncrief was known for his versatility on the court, particularly given his 6′4″ stature, but was most known for his tenacious defensive plays. Although he was thought of as one of the greatest shooting guards of his time, he was never able to get to the Finals, as the Bucks frequently came up short in the Eastern Conference Finals. Moncrief was named the NBA Defensive Player of the Year for the 1982–83 and 1983–84 seasons. He also made the All-Star team for five consecutive years and was named to the All-NBA first team for the 1982–83 season. Moncrief averaged over 20 points per game in four seasons of his career and finished his 11-season NBA career with an average of 15.6 PPG.
Among Moncrief's admirers was All-Star Michael Jordan who once described his on-court intensity to an L.A. Times reporter: "When you play against Moncrief, you're in for a night of all-around basketball. He'll hound you everywhere you go, both ends of the court. You just expect it."
Moncrief was elected to the Wisconsin Athletic Hall of Fame in 1998.
Moncrief was the head coach at the University of Arkansas-Little Rock for one season, 1999–2000. The Trojans finished with a record of 4 wins and 24 losses in Moncrief's only season.
In 2006, Moncrief returned to basketball as the head coach of the Fort Worth Flyers, a professional basketball team in the NBA D-League. He rejoined the NBA in October 2007 when he became the shooting coach for the Golden State Warriors. In 2011, he returned to the Milwaukee Bucks as an assistant coach.
It was announced in July 2013 that Moncrief would analyze and commentate Bucks games for FSN Wisconsin.
Moncrief's son Brett was a wide receiver for Mississippi Gulf Coast Community College and Troy University. His nephew Albrey Battle played eight seasons in the Arena Football League and for the San Francisco Demons of the XFL.