He was an alumnus of Sequoia High School and then scored 1,000 points in three years playing college basketball for the California Golden Bears.

The 6-foot-0, 170-pound point guard played with the Warriors for five seasons and part of a sixth until he was waived in early January 1978.

After his release, Johnson was signed by the Washington Bullets in January, 1978, after a season-ending injury to Phil Chenier.

Johnson averaged 8.3 points, 2.4 rebounds and 2.1 assists as a member of the 1977–78 NBA Championship team.

The Bullets topped the Atlanta Hawks, San Antonio Spurs and Philadelphia 76ers to reach the championship round.