Iaquinta wrestled at Wantagh High School and went on to earn his associate degree from Nassau Community College, where he also wrestled. Before turning pro, Iaquinta had a perfect amateur record of 14-0. Iaquinta began his pro MMA career fighting for the Ring of Combat promotion. There, he earned a record of 5-1-1.
Iaquinta was one of 32 lightweight fighters announced by the UFC to participate in first live season of The Ultimate Fighter reality show. Iaquinta advanced into the TUF house by defeating Jon Tuck by unanimous decision after one round. Afterwards, he was chosen as first pick for Team Faber.
After his team lost the first two matches, Iaquinta earned the first win for Team Faber by defeating Myles Jury via split decision after three rounds.
In the quarter-finals, Iaquinta fought Team Faber teammate, Andy Ogle. Iaquinta won via TKO in the closing moments of round one. The win advanced Iaquinta into the semi-finals where he faced Team Cruz's Vinc Pichel. Iaquinta defeated Pichel via unanimous decision after two rounds, and moved onto the finals against teammate Michael Chiesa.
Iaquinta officially made his UFC debut at The Ultimate Fighter 15 Finale on June 1, 2012 against Michael Chiesa to determine the winner of The Ultimate Fighter: Live. Iaquinta lost to Chiesa by rear naked choke early in the first round.
Iaquinta was expected to face Joe Proctor on April 27, 2013 at UFC 159. However, the bout was scrapped as both fighters sustained training injuries leading up to the fight.
Iaquinta faced Ryan Couture on August 31, 2013 at UFC 164, replacing an injured Quinn Mulhern. He won the bout via unanimous decision after dominating the fight on the feet and negating all of Couture's takedown attempts.
Iaquinta was expected to face Anthony Njokuani on October 26, 2013 at UFC Fight Night 30, replacing an injured Paul Taylor On September 24, Njokuani pulled out of the event with an injury. Iaquinta instead faced Piotr Hallmann. He won the fight by unanimous decision.
Iaquinta faced debuting Kevin Lee at UFC 169 on February 1, 2014. He won the fight via unanimous decision.
Iaquinta faced Mitch Clarke at UFC 173 on May 24, 2014. He lost the fight via technical submission in the second round.
Iaquinta faced Rodrigo Damm at UFC Fight Night 50 on September 5, 2014. Iaquinta defeated Damm via third-round TKO.
Iaquinta faced Ross Pearson on November 8, 2014 at UFC Fight Night 55. Despite being the underdog, Iaquinta won the fight via TKO in the second round.
Iaquinta faced Joe Lauzon on January 31, 2015 at UFC 183. He won the fight via TKO in the second round.
Iaquinta faced Jorge Masvidal on April 4, 2015 at UFC Fight Night 63. He won the bout via split decision. 13 of 15 media outlets scored the bout in favor of Masvidal.
Iaquinta was expected to face Bobby Green on July 15, 2015, at UFC Fight Night 71. However, Green pulled out of the fight in mid-June citing an undisclosed injury and was replaced by Gilbert Melendez. Subsequently, Melendez was removed from the card on July 6 after it was revealed that he tested positive for performance-enhancing drugs after his previous fight at UFC 188. In turn, Iaquinta was removed from the card as well.
Iaquinta was expected to face Thiago Alves on November 12, 2016 at UFC 205. However, Iaquinta announced on September 19 that he would not be taking the fight due to a contract dispute with the promotion.
After two years away from the sport, Iaquinta returned to face Diego Sanchez on April 22, 2017 at UFC Fight Night 108. He won the fight via knockout in the first round.