Ruby was born in Wichita Falls, Texas. He started racing in the late 1940s on motorcycles and on the local midget racing scene.
On the outbreak of war in Korea, he was drafted but broke his leg in a racing accident and ended up serving in a field hospital.
After completing his service he returned to midget racing and also made his debut in sports cars.
In 1959 he moved up to racing sprint cars in USAC sanctioned events and in 1960 drove race Indycars for JC Agajanian. He made his debut at Indianapolis that year and he won his first Indycar race at Milwaukee the following year.
He raced an ex-Jim Hall, square-bodied Lotus 18 in the 1961 US Grand Prix at Watkins Glen entered by J Frank Harrison. He retired after 76 laps with magneto failure.
Ruby raced on in Indycars during 1962 and 1963 but it was not util late 1964 that he took his second victory at Phoenix. He finished third at Indy that year, his best finish in the race.
Often reffered to as the best driver never to have won the Indy 500, Ruby's luck at Indianapolis was dismal. He led the race on five occasions. In 1966 he was leading comfortably when he black-flagged for leaking oil. In 1968 he was leading with just 25 laps to go when he went out with mechanical failure. In 1969 he was a whole lap ahead when he pulled away prematurely from a refueling stop with the hose still attached. The tank was damaged and it's contents were dumped all over the pit lane. He led again in 1970 and 1971 but on both occasion went out with mechanical failure.
In sports car racing he enjoyed better luck. A works driver for Ford, Ruby played a key role in Ford Motor Company's GT40 program in the mid-1960's. He won the Daytona 24 Hours in a GT40 in 1965 and won there again driving a MkII GT40 in 1966 as well as winning the Sebring 12 hour race.
Later in the year he escaped from a plane crash with only minor injuries. In Indycars he took another win at Phoenix in 1967 driving the Mongoose-Offenhauserand followed this with a win at Langhorne.
In 1968 he twice won at Milwaukee. His last victory came in 1970 driving a Mongoose at Trenton.
He continued to enter the 500 until 1978, racing at the Speedway 18 times. In 1978 he failed to qualify after suffering a number of engine failures in practice and decided that it was time to quit.
After racing he invested in some small oil wells. He died at the age of 81 in his hometown of Wichita Falls, Texas