Andy is a former resident of Springfield, Ohio. He graduated from Springfield’s North High School in 1998 and went on to serve three years with the U.S. Army’s 101st Airborne Division before attending Evergreen State College and becoming a journalist with Indymedia.org.  In December 2001, he went to Israel with a pro-Palestinian activist group pushing for an end to Israeli occupation. The following summer, he went to Colombia, South America, to study nonviolent resistance, and to Northern Ireland. In the Pacific Northwest, he joined protests against the World Trade Organization and was arrested in Seattle in April 2002 for interfering with a police officer.

On November 19, 2002, at 1:27 am, Mickel shot and killed Officer David Mobilio of the Red Bluff, California Police Department. Mobilio was shot twice in the back, and once in the head at “very close range.” A handmade “Don’t Tread on Us” flag was left beside Mobilio’s body. There were no witnesses to the killing, and the crime would have gone unsolved had there not been Internet postings about the crime six days later. The postings read, “Hello Everyone, my name’s Andy. I killed a Police Officer in Red Bluff, California in a motion to bring attention to, and halt, the police-state tactics that have come to be used throughout our country. Now I’m coming forward, to explain that this killing was also an action against corporate irresponsibility.”

Mickel said that “prior to my actions in Red Bluff, I formed a corporation under the name ‘Proud and Insolent Youth Incorporated,’ so that I could use the destructive immunity of corporations and turn it on something that actually should be destroyed.” The name is taken from the novel Peter Pan written by Scottish author J. M. Barrie. Mickel wrote, “Just before their final duel and Capt. Hook’s demise, Hook said to Peter, ‘Proud and insolent youth, prepare to meet thy doom.’"

Mickel insisted on representing himself during his trialIn April 2005, Mickel was convicted of one count of first-degree murder. He was subsequently sentenced to death, and was held on Death Row at San Quentin State Prison while awaiting his automatic appeal to the California Supreme Court.

In September 2009, The California Supreme Court, declaring that “In California, a criminal defendant has no right to represent himself or herself on appeal,” appointed attorney Lawrence A. Gibbs to represent Mickel for his automatic appeal. On December 19, 2016, the California supreme court upheld Mickel's conviction and sentence.