Born in Washington, D.C., Johnson attended Colonial Beach High School in Westmoreland County, Virginia, where he averaged 22.2 points and 12.5 rebounds in his final season.

He was then part of Laurinburg Institute's prep school national championship team under coach Chris Chaney in 2005.

He averaged 8.6 points, 3.9 rebounds and 2.7 blocks per game as a senior and shot 42 percent from three-point range.

[4] After a quick pre-season stint with the Boston Celtics,[5] Johnson joined the Dakota Wizards of the NBA D-League.

[19][20] After playing for the Timberwolves in the Las Vegas Summer League and spending pre-season with the team,[5] Johnson was waived on October 26, 2013.

[22] After spending pre-season with the Miami Heat,[23][24] Johnson returned to China for the start of the 2014–15 season to play for the Zhejiang Golden Bulls as a short-term injury replacement for Charles Gaines.

[29] In July 2016, Johnson played for the Portland Trail Blazers in the Las Vegas Summer League.

[30] In April 2019, he played for Shabab Al Ahli during the FIBA Asia Champions Cup GBA Qualifiers.

[33] After a stint in the Dominican Republic with Parque Hostos, Johnson moved to Saudi Arabia in December 2021 to play for Al Nasr.

[36] On July 24, 2024, Johnson signed with New Taipei Kings of the Taiwan Professional Basketball League (TPBL).