The nine-song, Larry Smith-produced project explored multiple music genres and was more experimental than their self-titled debut which was released the year before.
King of Rock also brought the group closer to the MTV audience they gained with "Rock Box" from their debut album. Run-D.M.C.'s label Profile intentionally crafted the "Rock Box" video to fit the 24-hour music video channel's nearly all-white format.
"We placed the group in an all-white setting with a white little boy and we shot it at Danceteria," Profile Records co-founder Cory Robbins told ROCK THE BELLS. "If we used a Black audience, MTV wouldn't have played it, because they would have considered it R&B. 'Rock Box' became the first rap video played on MTV so it worked."