In January 2003, Barry made his USA Pro Wrestling debut as part of a USA Pro gauntlet title nine man gauntlet match. Barry made his New York Wrestling Connection in February 2003 defeating Armand DeMuerto. Later that same night, Barry defeated Johnny Ova to become the NYWC Light Heavyweight Champion. In late 2004, Barry defeated Jay Lethal in a NYWC light heavyweight championship contendership match. The next month both Lethal and Barry lost to Joey Matthews in a three-way title match for the then vacant NYWC Heavyweight Championship. In early 2005, Barry was involved in a four-way NYWC Championship match, losing to Joey Matthews. In 2005, Ken Scampi and Dan Barry formed Team Tremendous. Later in 2005, Team Tremendous defeated The Dead Presidents and Brett Matthews and Brian Myers to become the New York Wrestling Connection Tag Team Champions for the first time. The duo lost the belts to Myers and Matthews in early 2006. In 2007, Barry won the NYWC Hi-Fi Championship by defeating plaZma. Dan Barry wrestled against Joey Braggiol in 2008 in a losing effort. This was his last match for NYWC until 2012 when he returned and took part in a battle royal. In May 2004, Barry debuted for WrestleJam for their debut show where he was defeated by Spider in a ladder match. At WrestleJam 6 in 2010, Barry defeated Benny Martinez. In 2012 at WrestleJam 9, Team Tremendous defeated Tru-Talent. At USA Pro's Elements of Xtreme 2005, Barry along with Jay Lethal, Grim Reefer, Deranged and Azrieal were defeated by Sonny Siaki. In 2010, Barry and Scampi defeated CT's Next Big Team to become the Connecticut Wrestling Entertainment Tag Team Champions for the first time. In 2013, Dan Barry and Ken Scampi disbanded Team Tremendous and Barry formed Tremendous Investigations Inc. alongside Bill Carr. The duo went on to adopt the Team Tremendous name. In 2014, Tremendous Investigations Inc. debuted for Combat Zone Wrestling defeating Milk Chocolate. Team Tremendous defeated The Young Bucks, The Beaver Boys, and then champions, O14K, at New Heights in 2015 to become the CZW Tag Team Champions for the first time. Team Tremendous successfully defended their belts against The Dollhouse. Barry and Sozio as Team Tremendous lost the CZW tag team titles to #TVReady. In 2016 at The Boss Is Back, Barry competed in a four-way match where he was defeated by debuting Flip Gordon. At Beyond Unbreakable, Team Tremendous and Biff Busick were defeated by the Young Bucks and Kevin Steen. At Beyond wrestling's Alive and Kicking, Barry took part of a ten man tag team elimination match teaming with the Juicy Product and the Doom Patrol, losing to the Young Bucks. Barry was the last person eliminated from his team. Team Tremendous won Beyond's tournament for tomorrow 3 by defeating the Young Bucks in the finals. Barry and Carr debuted for Evolve at Evolve 38, defeating Earl Cooter and Jody Kristofferson. At Evolve 54, Team Tremendous defeated Drew Gulak and Anthony Nese. Team Tremendous defeated Roppongi Vice at DREAMWAVE Fight Before Christmas in 2015. In 2017, Barry debuted for Full Impact Pro, defeating Billy Barboza. Later the same night he was defeated by Anthony Henry. At House of Hardcore 32, The Spirit Squad defeated Team Tremendous.