As a college wrestler for Penn State University, Cummins was a two-time NCAA Division I All-American and 2004 runner-up as well as a two-time US National Team Member. He made the transition to mixed martial arts in 2010. He made his professional debut on December 4, 2010, facing Terrell Brown at Strikeforce: Henderson vs. Babalu II. Cummins won his debut fight by first round TKO.
Cummins saw his fight career stalled in 2011 when he and fellow MMA fighter Eric Bradley were sentenced to jail in a case relating to felony burglary charges resulting from, what Cummins considers a fraternity prank at Penn State University. However the prosecution did not see it as a "prank" indeed there were multiple fraternities victimized, with items of a considerable value being taken; laptops, televisions etc.
Cummins fought Tasi Edwards at ProElite 3 on January 21, 2012. He won the fight via arm-triangle.
Cummins then fought Ricky Pulu at Xplode Fight Series: Revancha on March 16, 2013. He won via first round TKO.
In what would be his last fight before signing with UFC, Cummins faced Willie Smalls at SCL: Chaos in the Cage on May 18, 2013. Cummins won via guillotine choke submission.
In February 2014, Cummins stepped up on short notice to replace the injured Rashad Evans against Daniel Cormier on February 22, 2014, at UFC 170. He lost the fight by first round TKO.
For his second fight with the promotion, Cummins was scheduled to fight Francimar Barroso on June 7, 2014 at UFC Fight Night 42. However, Barroso was forced out of the bout due to an injury and replaced by promotional newcomer Roger Narvaez. Cummins won the fight via second round TKO.
Cummins faced Kyle Kingsbury on July 26, 2014 at UFC on Fox 12. He won the fight via dominant unanimous decision.
Cummins faced Antônio Carlos Júnior on December 20, 2014 at UFC Fight Night 58. He won the one-sided fight by unanimous decision.
Cummins faced Ovince Saint Preux on April 18, 2015 at UFC on Fox 15. He lost the fight via knockout in the first round.
Cummins faced Rafael Cavalcante on August 1, 2015 at UFC 190. He won the fight via TKO due to elbows in the third round.
Cummins faced Glover Teixeira on November 7, 2015 at UFC Fight Night 77. He lost the fight via TKO in the second round.
Cummins next faced Antônio Rogério Nogueira on May 14, 2016 at UFC 198. He lost the fight via TKO in the first round.
Cummins was expected to face Gian Villante on December 9, 2016 at UFC Fight Night 102. However, Cummins pulled out of the fight on December 2 citing a staph infection. He was replaced by promotional newcomer Saparbek Safarov.
Cummins faced Jan Błachowicz on April 8, 2017 at UFC 210. He won the bout by majority decision.
A rescheduled bout with Gian Villante eventually took place on July 22, 2017 at UFC on Fox 25. Cummins won the back-and-forth fight via split decision.
Cummins is expected to face Corey Anderson on November 4, 2017 at UFC 217.