[2] He challenged once for the vacant WBC Silver middleweight title, losing in his final fight to Julio César Chávez Jr.[3] As an amateur Duddy fought 130 times, winning 100 of his bouts.
[10] Duddy began 2004 by stepping up his opponent quality a notch, when he met Ken Hock on 9 January 2004 in Uncasville, Connecticut.
This undercard was televised in the United States on ESPN, with Duddy and Pierre fighting the semi-main event of the card, which was headlined by heavyweight Kevin McBride, who later defeated Mike Tyson.
On the undercard of 10 June 2006 Miguel Cotto–Paul Malignaggi Top Rank Pay-Per-View fight, Duddy took on the experienced fighter Alfredo Cuevas, who in 2004 went the 12 round distance with former middleweight champion Jermain Taylor.
Duddy won with a unanimous 90–81, 89-82 and 88-83 decision when the fight was stopped after the ninth round by referee Steve Smoger, due to heavy bleeding from Bonsante's forehead caused by an earlier accidental headbutt.
[16] Duddy defeated Michael Medina of Monterrey, Mexico via a split decision on 13 March 2010, on the undercard of the Pacquaio/Clottey WBO Welterweight Championship.
In the statement, Duddy cited a lack of desire, saying, "I no longer have the enthusiasm and willingness to make the sacrifices that are necessary to honor the craft of prizefighting", and stated that his decision is final, scuppering plans for an all-Irish showdown at Foxwoods Resort against Andy Lee.
[21] In 2012, Duddy played the bartender in the Matt Glasson short film Hard Times and portrayed the character Mark Sullivan in the online series The Wronged One (2010-2012, 2016), a revenge-thriller based on a graphic novel.
[22] In January 2016, Latino Review reported The Wrong One had the attention of IFC (U.S. TV network), formerly the Independent Film Channel.
[24] In the 2013 production of For Love by Irish actress, Laoisa Sexton's play about 3 single women in Dublin, Ireland and the men in their lives, Duddy portrayed all the male characters.
[30][31][32][33] His work with Sale and De Niro on Grudge Match led to Duddy's casting in the Roberto Durán biopic Hands of Stone (2016).
De Niro himself called to offer Duddy the role of legendary Scottish boxer Ken Buchanan after another actor withdrew from the part.
Interviewed by American sports writer Thomas Hauser, Duddy recalled, "Filming Hands of Stone was an incredible experience.