As an actor Harley appeared in over a dozen films as well as many TV shows in the 1980s and 1990s including cult films The Believers; "Someone To Watch Over Me"; The Fly II; Cohen and Tate and the TV series Sister Kate and Dudley. His most recent roles were in the 2000 film, "Shriek If You Know What I Did Last Friday the Thirteenth". and the 2004 film Kinsey

Harley was also the frontman of "The Harley Cross Band" in the early 2000s and has recently started a new music project with Lauren Turk called The New History

Harley was also the co-founder of Interconnected, a Los Angeles-based creative agency and production company, that he started in 2011 with his friend and Business partner Nirvan Mullick. Through Interconnected, Harley and Nirvan produced the viral video Caine's Arcade and the follow-up Caine's Arcade 2. After the viral success of Caine's Arcade, Harley and Nirvan co-founded the Imagination Foundation, a non-profit organization whose mission is to "find, foster and fund creativity and entrepreneurship in kids".

In 2015 he co-created the after school music education program Play with Music, which focuses on bringing relevant music education to at-risk youth. The program is currently running at Allen Leroy Locke High School in South Los Angeles.

He was co-founder, CEO, and artistic Director of Hint Mint Inc., a designer breath mint/ candy company that was master licensed to Giftcraft LLC (a Toronto based gift company) in 2016.

In early 2017, Harley co-founded Land Core USA . The organisation is focused on passing US federal legislation that gives market based solutions for American farmers to adopt existing USDA soil health management practices that address food security and wether resilience.