Johnson arrived at Hendrick Motorsports full-time in 2002 after a career that passed through off-road racing, the American Speed Association, and the NASCAR Busch Series. His talent was identified by Jeff Gordon, who became a co-owner of the No. 48 car and sponsored Johnson's entry into the team. Johnson finished fifth in points in his rookie season, second in both 2003 and 2004, and fifth in 2005, establishing himself as a consistent front-runner without yet winning the championship.
His long-time crew chief Chad Knaus joined the No. 48 operation from its outset and formed one of the most analytically rigorous driver-crew chief partnerships in NASCAR history. Knaus's preparation, strategic acuity, and relentless attention to rule compliance — including several notable penalties for technical violations — became central to the team's competitive identity.
Johnson won his first championship in 2006 after rallying from eighth in the points standings during the Chase for the Championship, winning five of the final ten races. He repeated in 2007 with ten race wins and again in 2008, becoming only the second driver after Cale Yarborough to win three consecutive titles. In 2009 he extended the streak to four, then in 2010 claimed a fifth consecutive championship — the first and only driver in NASCAR history to accomplish the feat.
During the five-year run, Johnson won at least three races in each season, accumulated 83 career wins through 2017, and qualified for the Chase for the Championship every year from 2004 to 2018. The five-season streak encompassed 35 race victories and positioned him as the central figure in NASCAR's competitive landscape.
After finishing sixth in 2011 and third in 2012, Johnson returned to championship form in 2013, winning six races including both Daytona race-weekend events in a single season — a feat not accomplished since Bobby Allison in 1982. His consistency through the Chase secured the title at Homestead-Miami Speedway.
Johnson's seventh title arrived under the elimination-style playoff format. He won three times during the season, the most important being a late victory at Martinsville Speedway that locked him into the final four-driver championship shootout at Homestead. Starting at the rear of the field due to a pre-race inspection penalty, Johnson drove through the pack and won the race and the championship simultaneously, tying Richard Petty and Dale Earnhardt at seven titles each.
The symmetry of the moment — a single race that simultaneously settled the championship, tied the all-time record, and came at the season finale — gave the achievement an unusual dramatic weight even by NASCAR standards.
Johnson and Knaus worked together from 2002 through the end of the 2018 season, a seventeen-year partnership described as the longest in NASCAR history between a driver and crew chief. Knaus's five championship victories with Johnson placed him among the most decorated crew chiefs in the sport. When the two separated after 2018, Johnson went winless in subsequent seasons.
Johnson was named Associated Press Male Athlete of the Year in 2009, the first racing driver to receive the honor. He later competed part-time in the IndyCar Series for Chip Ganassi Racing from 2021 to 2022, finishing as Indianapolis 500 Rookie of the Year in 2022. He has been involved in team ownership at Legacy Motor Club. His seven championships remain tied for the most in NASCAR history and his five consecutive titles stand as an unmatched achievement in American motorsport.