Edmunds showed an early aptitude for both driving and fabrication. His first contact with Kurtis midget cars led him to modify the nose from the factory design to his own specification — a sign of the constructive instinct that would define the second half of his career. His mechanical reputation reached Eddie Kuzma, the prominent Indianapolis car builder, who hired Edmunds to repair the dent in Jimmy Bryan's car after Bryan had kicked it in frustration.
Edmunds made his first start at Indianapolis Motor Speedway in 1957 and earned the 1957 Indianapolis 500 Rookie of the Year award after finishing nineteenth. He was preferred over a competitive rookie field that included Bill Cheesbourg, Elmer George, Mike Magill, and Eddie Sachs. His Indianapolis career was cut short when a serious practice accident at the Speedway in 1958 ended his time as a competitive Indy entrant.
Following the end of his driving career, Edmunds founded Autoresearch, Inc. in Anaheim, California. The company specialized in building midget cars and sprint cars, and its chassis won several National Midget Championships in the late 1960s and early 1970s. The quality and consistency of Autoresearch machinery established Edmunds as a leading constructor in American oval racing during this period.
His skills extended to sports car construction: Edmunds created the blueprints and performed most of the fabrication work on the original Bill Thomas Cheetah prototype sports car racer, a high-performance Chevrolet-powered machine intended to challenge Shelby's Cobra on road courses. The Cheetah project was ultimately cut short by fire, but the original prototype work stood as evidence of Edmunds' range as a builder.
In the 1970s, Edmunds pivoted toward Formula Super Vee, becoming a prolific constructor of cars for that class. Formula Super Vee operated as a developmental ladder series primarily in North America and gave Edmunds another arena in which to demonstrate his chassis-building precision.
In a project far outside motorsport, Edmunds built Evel Knievel's Snake River Canyon Sky Cycle — the steam-powered rocket used in Knievel's 1974 attempted jump across the Snake River Canyon in Twin Falls, Idaho. The assignment demonstrated the breadth of Edmunds' engineering and fabrication abilities.
Later in life, Edmunds became a collector and restorer of historic race cars, preserving machinery from American racing's earlier decades.
Edmunds was inducted into the National Sprint Car Hall of Fame in 1991 and the National Midget Auto Racing Hall of Fame in 1994, recognizing his contributions as both a competitor and a constructor in two of American oval racing's most demanding disciplines.
He died in August 2020 in Gold Beach, Oregon, at the age of 89.