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."

Where "Rock Box" was the only song to blend genres on Run-D.M.C.'s nearly drum-machine-only debut album, King of Rock explored many. The album's opener "Rock The House" is essentially an instrumental version of the title track "King of Rock" with vocal snippets and reverb effects thrown in. At a time before most rap albums contained skits or interludes, this was pretty groundbreaking.

"Rock The House" blends right into D.M.C.'s powerful acapella intro for "King of Rock" which picks up where "Rock Box" left off. The rock guitar line is played by guitarist Eddie Martinez who also played the guitar line for "Rock Box." The video for "King of Rock" features Run and D visiting a Rock & Roll museum where character actor Larry Bud Melman tells them that they aren't allowed to enter. Run and D.M.C. proceed to mock the museum's video presentations of Jerry Lee Lewis, Little Richard and other Rock icons before trashing then exiting the museum. This video would be responsible for the group's further crossover success, particularly with the MTV audience.

Reggae legend Yellowman helped Run-D.M.C. bend genres by appearing on "Roots, Rap, Reggae." The song was the first time that a major reggae artist collaborated with a rap act. Continuing the rock/rap hybrid "Jam Master Jammin'" was a guitar-heavy tribute to Jam Master Jay. The single for "Jam Master Jammin'" contained a remix produced by Rick Rubin. This marked Rubin's first time working with the group.

"You're Blind' was a slow-tempo rock song with dope 808 drum programming, as well as the social commentary that started with the group's debut "It's Like That." The cautionary tale describes the wanna be criminals — "You're standin' on the corner cold playin' the post, 'cus another sucka said you was chillin the most."

"Can You Rock it Like This" is an uptempo rock song written by up-and-coming MC, LL COOL J. "Can You Rock It Like This" was featured prominently in the movie Krush Groove which was released in the same year as King of Rock. "You Talk Too Much" is a song describing the neighborhood blabbermouth and "It's Not Funny" is a light-hearted song chronicling several serious situations with an Eddie Murphy vocal scratch as the hook.

Perhaps the album's most underrated song is the drum machine heavy "Daryll & Joe (Krush Groove 3)" which belongs to a trilogy of songs that include "Sucker Mc's," "Hollis Crew," and "Together Forever." King of Rock exposed Run-D.M.C. to a wider audience, ultimately leading to their highest-selling and most celebrated album one year later.

King Of Rock was Run-DMC's first experimental album. It was the project that positioned the group to achieve (even more) massive MTV success, and it introduced the group to audiences that had never experienced Hip-Hop. 40 years later it remains one of the group's most ambitious offerings.