While Cash's outlaw projected image was definitively attached to his name, the Outlaw Country movement of the 60s/70s wasn't directly attached to Cash's music, instead was inspired by his refusal to conform to the standards of the country music genre. He inspired some of his friends in the industry to spur on the progressive genre hybrid that abolished the conformity that society required in the country music genre. With artists like The Beatles, Bob Dylan and The Rolling Stones rebelling against societies conformity, Outlaw Country came popular with songs about drinking, masculinity and drugs. While he's not always directly associated with the movement, his style of music has the same approach to what the other front-men of the movement also held.
He did become directly involved in a later decade when he joined the movements pioneering influences to create an Outlaw Country supergroup. The group, known as The Highwaymen featured Cash, Waylon Jennings, Willie Nelson and Kris Kristofferson. They released three studio albums together.