Line grew up near Brainerd International Raceway in Minnesota, where exposure to motorsport was formative. He learned engine repair from his father, and as a teenager acquired a 1970 Buick GS to race at the local track. He served in the United States Air Force from 1987 to 1991, and after leaving the military began applying his technical aptitude in professional motorsport contexts. From 1998, he worked for Joe Gibbs' NASCAR team as Chief Dynamometer Engine Specialist, a role that sharpened his expertise in high-performance engine development before he transitioned to full-time driving.
His first NHRA race as a driver came in 1985, when he competed in a 1968 Chevelle at Brainerd International Raceway. In 1993, he won both the NHRA Division 5 championship and the NHRA National Stock Championship, establishing himself as a competitive force in the amateur ranks.
Line moved into full-time Pro Stock competition in the NHRA Mello Yello Drag Racing Series driving for Summit Racing Equipment/KB Racing alongside teammate Greg Anderson. He was named NHRA Rookie of the Year in 2004, the same season he finished second in the Pro Stock championship — behind Anderson — despite being in his first full year at the top level.
He won his first Pro Stock world championship in 2006, adding further titles in 2011 and 2016. The three championships placed him among the elite of the modern Pro Stock era. His career totals of 49 Pro Stock wins and 51 overall NHRA victories (including two Sportsman class wins) reflect remarkable longevity and competitiveness.
His best career elapsed time was 6.455 seconds, and his best speed 215.17 mph (346.28 km/h), both marks of a driver capable of extracting maximum performance from his equipment. In a separate record-setting effort away from the main NHRA calendar, Line broke the NHRA A/Modified Production Speed Record at the Bonneville Salt Flats in 2012, running 225.246 mph with the Jesel Land Speed/Summit Racing Team.
Line retired from full-time Pro Stock driving following the 2020 season. Over his career he drove for Elite Motorsports and raced the JHG Racing Chevrolet Camaro in the final years of his tenure. He resided in Terrell, North Carolina with his wife Cindy and their children.
With three Pro Stock championships and 49 class victories, Jason Line stands as one of the most successful Pro Stock drivers of the 2000s and 2010s. His dual identity as both a technically sophisticated engine specialist and a front-running competitor gave him a distinct profile within the class. His 2004 Rookie of the Year award and near-championship in his debut season foreshadowed a career defined by precision and consistency at the top of professional drag racing.