NASCAR's top series had carried the Winston Cup name since 1971, when R.J. Reynolds became title sponsor to circumvent the Public Health Cigarette Smoking Act's ban on television tobacco advertising. By 2002, however, R.J. Reynolds notified NASCAR leadership that it would end its sponsorship prematurely at the conclusion of the 2003 season. NASCAR negotiated a replacement deal with Nextel, a telecommunications company, and in 2004 the series officially became the Nextel Cup Series.
The transition coincided with NASCAR's broader ambitions to modernize the sport's image, expand its audience beyond its traditional southeastern United States base, and attract corporate partners outside the tobacco industry. The Nextel deal represented a significant shift in how NASCAR positioned itself commercially.
The most consequential structural change introduced during the Nextel Cup era was the Chase for the Championship, a playoff system that debuted in 2004. Conceived to maintain competitive tension throughout the full season, the Chase system seeded the ten highest-scoring drivers after the first 26 races of the season into a ten-race playoff for the title. The original format reset all Chase contenders to approximately equal points, with modest bonuses for regular-season wins, then ran the standard points system over the final ten races to determine the champion.
The system was expanded in 2007 to include twelve drivers in the Chase field. Its introduction marked a decisive break from the previous format, under which a driver could theoretically clinch the championship before the final race, or even several races before the season's end. The Chase was designed partly to sustain television ratings deep into the autumn, when NASCAR's schedule ran concurrent with the NFL season.
In 2005, Sprint Corporation acquired Nextel, merging the two telecommunications companies. The Cup Series continued under the Nextel Cup name through the 2007 season, but NASCAR and the renamed Sprint Nextel agreed to rebrand the series beginning with the 2008 season, after which it became known as the NASCAR Sprint Cup Series. The transition was managed smoothly, preserving the existing sponsorship relationship under the merged company's Sprint brand.
Under Brian France, who assumed the CEO and chairman role in 2003, NASCAR leveraged the Nextel Cup transition to negotiate a major television contract worth $4.5 billion for an initial ten-race broadcast period, along with a subsequent multibillion-dollar deal with NBC. The series also saw Toyota admitted as a competing manufacturer for the first time during this period, broadening the field beyond the historic American manufacturers Chevrolet, Ford, and Dodge.
The Nextel Cup years also saw NASCAR deepen its commitment to driver safety, driven in part by the death of Dale Earnhardt at the 2001 Daytona 500. During this period the HANS device was mandated for all drivers, and SAFER barriers were progressively installed around the outside walls, and later the inside walls, of every track on the schedule.
The Nextel Cup era is remembered as the period when NASCAR's popularity reached its television peak. Ratings had climbed through the 1990s and crested in the mid-2000s before beginning a gradual decline from approximately 2007 onward, attributed by critics to changing schedules, venue choices, and shifting fan demographics. The Chase playoff format introduced during the Nextel Cup years remained the structural backbone of NASCAR's championship system through multiple subsequent rebranding cycles — Sprint Cup (2008–2016), Monster Energy NASCAR Cup Series (2017–2019), and the current NASCAR Cup Series (2020–present). The Nextel Cup thus represents both the commercial high-water mark and the beginning of a period of institutional self-examination for the sport.