Sampey grew up in New Orleans and entered drag racing as an adult, making her professional debut in 1996 aboard a Suzuki motorcycle. Her primary sponsors through her peak years included R.J. Reynolds' Winston brand and the U.S. Army. She also raced under her married names Angelle Seeling and Angelle Savoie at various points in her career.
Sampey's consistency from her debut was remarkable: she holds an active record of 182 consecutive races without a Did Not Qualify, a streak dating back to her very first professional start. Over 506 competitive rounds she won 364, a win-per-round ratio of 71.9 percent.
Her three consecutive championship seasons from 2000 to 2002 defined the era in Pro Stock Motorcycle. During that stretch she outpaced the all-time class leader Dave Schultz on wins per season and set the pace for the discipline. On June 23, 2007 at Old Bridge Township Raceway Park in Englishtown, New Jersey, she set the national Pro Stock Motorcycle elapsed time record with a 6.871-second run, the same day she claimed her 42nd career pole position.
Following a win in Houston, Texas on April 1, 2007, Sampey stood just five victories short of Schultz's all-time Pro Stock Motorcycle wins record. Lack of sponsorship kept her out of the 2009 season, breaking her qualification streak, and in March 2010 she announced her retirement.
In September 2014 it was announced that Sampey would return to competition before the end of that season and would chase the championship in 2015. She raced through the 2022 season before departing Vance and Hines Suzuki at the close of that year.
In August 2023 Sampey transitioned into Top Alcohol Dragster, joining the AB Motorsports Accelerate program run by former Pro Stock Motorcycle rival Antron Brown. After earning her A/Fuel licence, she debuted at the Texas Motorplex. In her first race she qualified sixteenth, then defeated Mike Coughlin in round one and Tony Stewart in the second round before falling to Kirk Wolf in the semifinals. Her stated long-term goal is a move into Top Fuel.
Along with Erica Enders, Shirley Muldowney, Brittany Force, and Christina Nielsen, Sampey stands as one of a very small group of women to have won a major professional motorsport championship. She, Enders, and Muldowney are the only three female drag racers to have scored more than ten NHRA event wins, and the only three women in the sport to win more than one championship in their respective divisions. Muldowney won three Top Fuel titles, Enders five Pro Stock titles, and Sampey three in Pro Stock Motorcycle.
With 46 career victories, Sampey is considered the second-winningest female competitor in professional motorsport history, behind Enders whose 47th win came in 2023. NHRA's Pro Stock Motorcycle class still measures its historical benchmarks in significant part against what Sampey accomplished during her dominant run at the turn of the millennium.