Belmont entered racing in the orbit of his brother Andy's operation, Andy Belmont Racing (ABR), which gave Kevin his first competitive opportunity and remained the team he returned to repeatedly across his career. His nephew Andrew Belmont and nephew Kyle Belmont have also competed in ARCA competition, making the Belmonts a multi-generational family in American stock car racing's developmental ranks.
Belmont made his ARCA debut in 2000 at Winchester Speedway, driving the No. 1 Ford for Andy Belmont Racing. He started 32nd and last and finished 25th. He attempted the following round at the Illinois State Fairgrounds dirt track but failed to qualify.
In 2001, Belmont ran nearly the full ARCA schedule — absent only from the season opener at Daytona International Speedway — across entries with Andy Belmont Racing, Joe Cooksey, and ML Motorsports. He finished eleventh in the final points standings, with a best result of tenth at Memphis Motorsports Park. That season complicated his driving record: Belmont was simultaneously serving as crew chief for Andy's No. 1 Ford, meaning most of his own entries were start-and-park appearances in a backup ABR car; he was classified as still running at the end of only five races.
In 2002, Belmont made a cleaner commitment to full-time driving by joining James Hylton Motorsports in the No. 48 Ford for the complete schedule. He produced his strongest body of results that season: four top-ten finishes, a best of seventh at Springfield, and an eleventh-place final points position that matched his 2001 standing but came with more genuine racing behind it.
His 2003 season was limited to two starts. At Atlanta Motor Speedway in the No. 38 Pontiac for ABR, he ran as high as twelfth before a broken rear end caused a crash and left him classified 28th. At Lowe's Motor Speedway, entered by Mark Mancinelli, he finished eighteenth.
After a five-year absence from competition, Belmont returned to ARCA in 2009 with Andy Belmont Racing, driving the No. 14 Ford. He ran five events: Kentucky Speedway (22nd), Toledo Speedway (30th, last car running), Pocono Raceway (21st), Michigan Speedway (21st), and Mansfield Motorsports Park (16th from 29th on the grid). The Mansfield race proved to be his final competitive start; he was replaced by Kory Rabenold for the rest of the season and did not return as a driver.
Following the end of his driving career, Belmont worked as a spotter for Mullins Racing, a role that kept him connected to the sport in a support capacity. His career combined modest but consistent results with a family context that made the distinction between driver, crew chief, and team member fluid throughout.