Selected second overall in the 1968 AFL/NFL Draft out of Tennessee, Bob Johnson holds a unique place in Cincinnati Bengals lore as the very first draft pick in franchise history. Head coach Paul Brown coveted a brainy, dependable pivot to set the baseline for his expansion offense, and Johnson answered the call by locking down the starting center job from the team's inaugural drive onward.

Johnson brought exceptional line-calling insight, precise snapping, and relentless technique to the pivot. In an era of heavy interior collisions, he anchored Paul Brown's front five by recognizing blitz patterns and keeping a clean pocket for early Bengals quarterbacks such as Greg Cook and Virgil Carter. Johnson stepped directly into the starting lineup as a rookie in 1968, starting all 14 games and earning an AFL All-Star selection in his debut campaign.

Consistency defined Johnson’s run at center. Across his first ten seasons (1968–1977), he started every single one of the 136 regular-season games he appeared in. He helped lead Cincinnati to its first two division titles in 1970 and 1973, serving as the team's offensive captain and primary interior pass blocker.

As the franchise transitioned into the late 1970s, Johnson stepped into a veteran backup and reserve snapper role for his final two campaigns. He retired following the 1979 season as the last remaining member of the original 1968 inaugural squad.

Johnson played in 154 regular-season games (136 starts) along with three postseason appearances. Shortly after his career ended, the Bengals retired his No. 54 jersey.