Glotzbach was named the ARCA series Rookie of the Year in 1964, establishing his credentials on oval tracks before his NASCAR activity intensified. He also attempted to qualify for both the 1969 and 1970 Indianapolis 500, though he failed to make the field in either attempt, reflecting the crossover ambitions common to American racing drivers of that era.
Glotzbach's first NASCAR Winston Cup start came in 1960. He never ran a full Cup schedule but competed in partial seasons consistently from 1967 through 1975, with 1968 being his busiest year at 22 of 48 events. Across his Cup career he recorded four wins and twelve pole positions.
In September 1969 at Talladega Superspeedway, Glotzbach set a world speed record of 199.466 mph driving the Chrysler Engineering No. 88 Dodge Charger Daytona. His car won the pole for the race, but Glotzbach and most other drivers sat out the event in protest over a tire dispute, leaving the speed mark as the defining achievement of that weekend.
At the 1969 Daytona 500, Glotzbach finished second after being passed on the final lap by LeeRoy Yarbrough, a result that highlighted both his pace and the cruel timing that can define a driver's legacy.
In late 1969, Glotzbach suffered a serious off-track incident in which he received broken ribs and was shot twice after dismissing an employee from his trucking company. He returned to racing the following season with one of the bullets still lodged in his upper arm, a detail noted in ABC's Wide World of Sports broadcast of the 1970 Daytona 500.
In July 1971, Glotzbach won the Volunteer 500 at Bristol Motor Speedway in a race that stands as a landmark of NASCAR history. The event at the .533-mile track was completed without a single caution flag, a rarity at any oval but especially at the short, high-banked Bristol layout. Glotzbach averaged 101.074 mph across a two hour, 38-minute race, requiring a mid-race relief stint from Friday Hassler. That average speed record stood for 53 years until Kyle Larson broke it at the 2024 running of the same race, averaging 101.277 mph — despite five caution periods in his version of the event.
Glotzbach's final NASCAR Cup start came in 1992, when he competed in seven events at the age of 53. He made a final qualifying attempt in 1994 for the inaugural Brickyard 400 at Indianapolis Motor Speedway but did not make the field. In later life he operated Charlie's Truck Sales in Sellersburg, Indiana.
On March 20, 2010, Glotzbach was involved in a serious crash during a charity legends race at Bristol Motor Speedway, sustaining injuries after a collision with Larry Pearson's car; both drivers recovered.
Glotzbach was found dead at his home in Jeffersonville, Indiana, on April 23, 2021, at the age of 82.
Glotzbach's career sits at an intersection of speed, toughness, and historical curiosity. His 199-mph Talladega record run captured a moment when stock car racing was exploring its absolute limits of velocity, while his caution-free Bristol win became the kind of durability record that endures because the conditions that produced it are almost impossible to replicate. His ability to continue racing at a high level after a near-career-ending shooting incident in 1969 added a chapter to his story that few in motorsport could match.