Leffler, a native of Long Beach, Calif., died Wednesday night from injuries suffered in a sprint car crash in New Jersey. The Delaware County (Pa.) medical examiner determined Leffler died from a blunt force neck injury. He was 37.
An avid Jones fan, Leffler considered the 1963 Indianapolis 500 winner his mentor dating back to his teenage years when he was working in the Torrance, Calif., shop alongside Jones' sons, Page and PJ.
"Jason was one of the nicest, most positive people I have ever been around," Jones said Friday by phone from California. "But that all changed when he got into a race car—his desire to succeed and do well, win was enormous. He was a competitor. He was a charger. Looking back now, he even had more fight and desire than I thought. Desire is a word that describes him well."
Jones recalled Leffler's father dropping him off at the race shop as a 13-year-old in the early morning so Leffler could learn how to work on midget cars.
"He's still around working 'til 2 a.m. helping with anything and everything," Jones said. "He loved racing and loved being in the shop with the boys. Jason was very close to our family for a long time—almost 25 years, and he was someone we grew up with and remained close to.
Jones said Leffler had unhealthy eating and exercise habits when he first began racing, but eventually saw the error of his ways.
"He was in bad shape, he'd eat hamburgers and junk food and 'fall out of the seat,'" Jones said. "But then he saw the benefits of working out and getting in shape to be a better driver and he sure wasn't afraid to work to become a better driver, which he did. Jason paid his dues for sure."
Leffler won four USAC Midget championships—three consecutive from 1997-99—and eventually followed Tony Stewart's path from sprint cars to IndyCar and then NASCAR. Leffler made 423 starts in NASCAR's three national series, winning the two Nationwide races and one Truck Series event in a career that began in 1999. He also made three IndyCar Series starts, finishing 17th in the 2000 Indianapolis 500.
Leffler's last full NASCAR season was 2011, when he ran the entire Nationwide schedule for Turner Motorsports. He finished sixth in the standings that season and hadn't had a steady NASCAR ride since, which led to him running as many sprint car races as possible this year.
"He drove the wheels off of everything and was so fun to watch in a midget or sprint car," Jones said. "Although he never found the success he wanted in Sprint Cup, Nationwide or the Truck Series, he always fought hard to be successful and always did his best in whatever car he was in that race or weekend. When he raced at Indianapolis in 2000 he was so proud to be part of the event. The 500 meant a lot to him—the track, the history of the event and the people involved."
Leffler was divorced and a doting father to his 5-year-old son, Charlie Dean.
His girlfriend on Thursday tweeted a photo of the couple kissing, posting "one day we'll dance at the dirt track to you and tequila and make me crazy and be married at the start finish line" at Indianapolis Motor Speedway.
Although not the biggest star or household name, Leffler was popular among his peers and his death hit many in NASCAR and IndyCar hard.
At the IndyCar race at the Milwaukee Mile, Ed Carpenter Racing team manager Tim Broyles designed a special decal of Leffler's nickname, 'LEFturn' that was offered to all the teams. Carpenter was a fellow USAC competitor with Leffler in the USAC midget and Silver Crown races in the early 2000s.
"Jason was such a fun guy to be around and we're all very lucky we got to work side-by-side and travel with him to races over the years," Jones said. "He'll be with us for a long time, forever."