Johnson attended the University of South Carolina in Columbia, South Carolina. Among other honors, she was named to the 1994, 1995 and 1996 All-Southeastern Conference first teams. She was also a finalist for the Wade Trophy and the Naismith Award in 1995.
Starting in 1999, Johnson played for the Orlando Miracle of the WNBA. The team moved to Connecticut in 2003 and is now known as the Connecticut Sun. Prior to the 2004 season, Johnson was traded to the San Antonio Silver Stars.
Johnson was a WNBA All-Star in 1999, 2000, 2002 and 2003.
She was also a member of the USA Basketball team winning the Gold Medal at the 2004 Summer Olympics.