Credico was once active on the comedy circuit, and at the age of 27 he made an appearance on The Tonight Show Starring Johnny Carson. During the appearance, he criticized U.S. foreign policy and compared Ambassador Jeane Kirkpatrick to Eva Braun; Credico was not invited back to the show, and some believe this is due to the Kirkpatrick impersonation. He was featured on the 1988 comedy album, "Strange Bedfellows: Comedy and Politics" along with Jimmy Tingle, Barry Crimmins, and Will Durst.
Credico spent four years in Tulia, Texas, bringing national attention to a racially-charged mass drug arrest. The Kunstler Fund produced an award-winning documentary on the subject entitled Tulia, Texas: Scenes from the drug war, written, directed and edited by Emily Kunstler and Sarah Kunstler. Credico is the subject of the film Sixty Spins Around the Sun, directed by comedian Laura Kightlinger.
Credico produced, directed and wrote the radio program 60 Mimics, and is a frequent guest on Live from the State Capitol with Fred Dicker, a political talk radio program on WGDJ in Albany, New York.
At age 37, Credico began a periodic campaign against New York state's Rockefeller drug laws, which he claimed were too harsh, disproportionately affecting the poor and minorities. Small changes softening the stiffest penalties were passed in the state legislature, which Credico thought were insufficient.
In 2009, Credico attended a meeting of the New York State Senate on Open Government dressed as the Greek philosopher Diogenes the Cynic, "seeking an honest politician."
On May 4, 2016, Credico's mentor, Roger Stone, announced that Credico had formed the group "Sanders' Supporters for Trump." While nothing seemed to have come of that effort, Credico's most notable appearance in the 2016 election cycle was headlining a Republican fund-raiser in Cayuga County, New York.
Credico ran as a Democratic primary challenger against Senator Chuck Schumer in 2010. Credico submitted petitions in an effort to get onto the Democratic Party primary ballot. The party chairman claimed that Credico only submitted a few pages' worth of petitions to the state, far short of the 15,000 necessary, a charge Credico denied. Credico threatened to throw his support to Republican candidate Carl Paladino in the gubernatorial race. He made the ballot.
Credico's campaign was supported by several actors and comedians, including Seinfeld co-creator Larry David, Roseanne Barr, and "Professor" Irwin Corey. He was nominated by the Libertarian Party of New York and the nascent "Anti-Prohibition Party" of Kristin "Manhattan Madam" Davis, though those parties do not have permanent ballot access and were required to petition their way onto the ballot. Credico finished with 25,975 votes (0.6%), in last place among the four candidates; in most jurisdictions, Credico was only given one ballot line despite petitioning for two.
Credico sued the New York State Board of Elections under the Equal Protection Clause of the Fourteenth Amendment because of this unfair treatment regarding ballot access. On June 19, 2013, the Federal District Court for the Eastern District of New York ruled in favor of Credico. The New York State Board of Elections did not appeal this decision.
Credico ran for the Democratic nominee for Mayor of New York City in the 2013 election. He received 12,685 votes (2.0%). He also appeared on the ballot in the general election with 14 other candidates, on the Tax Wall Street line, receiving 654 votes (0.1%).
Credico challenged incumbent Democratic Governor Andrew Cuomo in the 2014 Democratic primary. He came in third among three candidates, with 20,760 votes (3.6%).