Joe Aitcheson Jr., who became one of America’s most heralded and successful steeplechase riders, a record he liked to say was matched only by the number of broken bones and lacerations he sustained, died May 24 at a hospice in Westminster, Md. He was 85.

The cause was pneumonia, said his daughter Jody Davis. Mr. Aitcheson lived in Laurel, Md., much of his adult life and moved to a Westminster retirement community about five years ago.

The 5-foot-10 horseman acquired dueling nicknames: Jumpin’ Joe and the Bionic Man. The monikers reflected the extraordinary sense of timing and balance he brought to the grueling sport he dominated for much of the 1960s as well as the grit and fearlessness that defined him in much of the steeplechase world for years afterward.

The Hall of Fame flat rider Angel Cordero recalled seeing Mr. Aitcheson at the Saratoga Race Course in New York. “He’d come into the room all busted up, shoulder strapped up, neck wrapped up, couldn’t walk straight,” Cordero once told an interviewer. “And I’d think there’s no way this guy can ride today. Then he’d go out and win.”

Mr. Aitcheson’s reputation was once summed up in a cartoon featuring a line of beautiful cars with license plates bearing the names of their owners, acclaimed jockeys such as Jean Cruguet, John Velasquez and Eddie Maple. The odd car out was a beat-up buggy awash in bandages and a dented plate that read “Aitcheson.”

Joe L. Aitcheson, Jr., one of the nation's leading steeplechase riders, leads Tusca Lee, a thoroughbred trained by his father, Joe L. Aitcheson Sr. at their family farm outside Laurel, Md., in 1964. (Henry Rohland/The Washington Post)

The National Museum of Racing’s Hall of Fame, where he was inducted in 1978, underscored the sportswriter Red Smith’s quip that Mr. Aitcheson seemingly was “held together with baling wire and tape.”

He had grown up on a farm in upper Montgomery County during the Depression and had been a football and boxing standout as a young man. He worked in carpentry and bricklaying and served two stints in the Navy before embarking on a professional steeplechase career at 28, an age when many such jockeys are thinking of hanging up their boots.

Mr. Aitcheson won 440 races over the next 21 years and a record-smashing seven North American championships in the 1960s, in addition to eight Virginia Gold Cups, seven Carolina Cups, six International Gold Cups and five Temple Gwathmeys, among others.

He rode such horses as the national champions Peal (1961), Amber Diver (1963), Bon Nouvel (1964, 1965 and 1968), Tuscalee (1966), Top Bid (1970) — in the Colonial Cup, the first steeplechase with a $100,000 purse — and Soothsayer (1972).

Charlie Colgan, a former executive director of the National Steeplechase Association, once called Mr. Aitcheson a “master tactician.”

“At every stage of a race, he knew where he was in relation to the entire field, and he was careful never to put another rider in harm’s way,” Colgan told the horse writer Laurel Scott. “He had an uncanny knack [for] finding the shortest way home, and he won a lot of races by simply saving more ground than anyone else.”

At its essence, the job was to gallop at racing speed over long distances and giant obstacles. Some courses, such as the Maryland Hunt Cup, feature high jumps of thick timber, making the leap daunting and potentially lethal.

Mr. Aitcheson was an insurance company’s worst nightmare, having endured an emergency room’s worth of broken ribs and collarbones, broken noses and skull fractures in the course of what he estimated were 150 falls from the saddle.

He told the Baltimore Sun that, to compete with a broken ankle, he once painted his cast brown to resemble a riding boot — in an apparently successful ruse to mislead race officials who might otherwise have disqualified him.

His most terrifying spill took place at New York’s Aqueduct Racetrack in 1965. “My horse rolled on me,” he told equestrian writer Peter Winants. “I punctured my lung, had a torn spleen, an injured kidney and broken ribs. It didn’t look good for a while.”

He said his family was told he might not survive the night. After weeks in the hospital and months of recovery, he said, he was written off as a rider. He was advised to consider a career as a trainer.

Instead, he remounted a series of lesser-known horses, culminating in a spectacular comeback in 1967 riding Leeds Don.

A decade later, as Mr. Aitcheson neared retirement from professional racing, he fell at Saratoga and broke his collarbone. He was determined to race a few days later at the prestigious New York Turf Writers Cup, riding a horse named Happy Intellectual.

With his injury, Mr. Aitcheson found galloping excruciatingly painful. He told Scott that he persuaded a veterinarian to feed him equine pain medication. The main event went well until the final turn, when Mr. Aitcheson said his legs went rubbery from exhaustion.

“I just grabbed the mane and held on,” he recalled. “I wasn’t squeezing or helping him along at all — I was just sitting there. I could hear whips popping behind me, and knew they were closing in the stretch, and that Happy would quit when they caught him, like he usually [did].”

The horse defied expectations, and they won by 1.5 lengths, a course record at the time.

Mr. Aitcheson’s professional career ended a few months later when he took a tumble and “got a hoof upside the eye,” causing double vision. He tried to brush it off but, at 49, few trainers would take him.

Joseph Leiter Aitcheson Jr. was born July 31, 1928, in Olney, Md., and he grew up on his family’s farm near Burtonsville, Md. He worked at his uncle’s riding stable next door, cleaning barns and guiding trail rides for $1 a day. The family was prominent in fox hunting and training circles.

After graduating from Montgomery Blair High School in Silver Spring, the younger Aitcheson joined the Navy at 17 and later served in the Korean War as a gunner’s mate on an aircraft carrier.

Following his discharge, he returned to Maryland and began his ascent as a professional steeplechase jockey.

“My father got a horse to break that bucked a lot,” he told Scott. “I broke it after a few spills, but it was still too spooky for the owner to fox hunt, so my dad talked him into running the horse at Saturday jump meets.”

The horse was Grand Chal, which Mr. Aitcheson rode to victory at the 1957 Virginia Gold Cup and soon became one of the country’s champion timber horses. Around that time, Mr. Aitcheson also began working with D.M. “Mikey” Smithwick and A.P. “Paddy” Smithwick of Hydes, Md., two of the country’s top trainers and riders.

Mr. Aitcheson’s marriages to Audrey Melbourne, Dorothy Montgomery and Jo Holbrunner ended in divorce. Survivors include a daughter from his second marriage, Jody Davis of Sykesville, Md.; a stepdaughter he adopted, Kathy Aitcheson; a sister, Jane Cartwright of Laurel; five grandchildren; and two great-grandchildren.

In retirement from racing, Mr. Aitcheson exercised horses at Laurel Park.

“I grew up poor,” he once told the Sun. “I wasn’t a smart person and the only jobs I had were as a laborer, driving trucks or carrying lumber. But I loved horses and, riding them, I felt like I really was somebody.”