Grubb was born in Floyd, Virginia, a small town in Floyd County, which had only one stoplight and an estimated 14,000 residents. Floyd is also the birthplace and childhood home of NASCAR legend Curtis Turner. His love of racing began to develop during his time at Floyd County High School. He built Late Model stock cars that competed in races throughout Virginia and the Carolinas. Grubb made a lasting impression upon his graduation in 1993, ranking 6th in a 156-pupil class. As a senior at the Virginia Polytechnic Institute and State University in 1998, Grubb was influential in the design of the school's "Tinker Bell" ATV used in competition. He graduated with a mechanical engineering degree that year through a co-op program with Volvo Trucks and General Motors. Grubb quoted this about his association with the co-op program: "That was a really good program. I worked within Volvo Heavy Trucks for the first four years . I was basically able to do five years of college with alternating semesters, so I got a year-and-a-half of work experience by the time I graduated. I was a junior design engineer and worked with people designing truck interiors - seats, dashes and all the integral parts of the interior of tractor-trailer rigs. My senior year I went to General Motors and worked on the Cadillac program that summer, basically working on mechanical systems, warranty reduction and power-steering systems. That was a good experience for me because it was my first time to actually move out of state and I got a chance to work with one of the Big Three auto companies."
Racing career
Grubb spent four years as an engineer with Hendrick Motorsports, before taking over the crew chief job temporarily for Jimmie Johnson's team at the 2006 Daytona 500, after regular crew chief Chad Knaus was suspended. Johnson went on to win that race for his first Daytona 500 victory. Johnson and Grubb went on to finish second at the 2006 Auto Club 500. Johnson won two weeks later, again with Grubb, in the 2006 UAW-DaimlerChrysler 400. In 2007, he was named the crew chief for Casey Mears' No. 25 Hendrick team, where he scored another win, at the Coca-Cola 600. In the 2008 season, Grubb moved to an administrative role with Hendrick Motorsports, supervising the No. 5 and the renumbered No. 88 teams. Grubb left Hendrick Motorsports at the end of this season to join the new Stewart-Haas Racing team to serve as Tony Stewart's crew chief in 2009. Grubb was the winning crew chief for Stewart at the 2009 NASCAR Sprint All-Star Race at Charlotte Motor Speedway. Grubb also guided Stewart to his first win as an owner/driver at the 2009 Pocono 500. During the 2011 season, Grubb led Stewart from a mediocre pre-chase effort to five chase victories and Stewart's third NASCAR Cup Championship by way of a 5-1 victory tiebreaker over Carl Edwards that NASCAR uses in the event of a tie in the points standings at the end of the season. This was Grubb's first championship. However, Grubb announced that he had been informed of his release prior to the fall Charlotte race. Grubb joined Joe Gibbs Racing and became the crew chief for Denny Hamlin and the No. 11 team in 2012, replacing Mike Ford. On July 29, 2014, Grubb was suspended six races for tampered firewall covers, which could lead to more downforce, during the Brickyard 400. In 2016, Grubb returned to Hendrick Motorsports to become the vehicle production director, which oversees chassis manufacturing. In 2017, he was named crew chief for the No. 5 car of Kasey Kahne for the last 9 races of the season starting at New Hampshire. On November 1, 2017, it was announced that Grubb will be the crew chief for William Byron for the 2018 Monster Energy NASCAR Cup Series season. On October 10, 2018, Hendrick Motorsports announced that Grubb will move on to a technical director position while Knaus takes over crew chief duties for the No. 24 in 2019.
