J. D. Smith, Jr., a two-time Pro Bowl running back with the San Francisco 49ers, who ranks sixth on the franchise's all-time rushing list with 4,370 yards, passed away at his home in Oakland, Calif. on Wednesday, April 1, 2015. He was 83 years old.

Nicknamed the "Cinderella Man" for his inauspicious route into the NFL, Smith, who played a total of 10 years – eight with the San Francisco 49ers and two with the Dallas Cowboys, began his NFL career as a 24-year old rookie and U.S. military veteran with two children.

Smith, drafted 10th in the fifteenth round (179th overall) by the Chicago Bears in the 1955 NFL Draft, spent a year completing his military duty in the United States Army during the Korean War before seeing any playing time with Chicago. Smith saw no playing time at halfback and was used sparingly by the Bears on defense. Picked up on waivers by the San Francisco 49ers from the Chicago Bears at the end of the 1956 season, Smith was also used on defense by the 49ers in his first year with the club.

Then in 1958, the 49ers moved his durable, hustling 210-pound frame over on offense. He responded favorably to the move and seized the opportunity. On December 7th, he had the team's longest run from scrimmage to date, 80-yards against the Green Bay Packers. Smith told 49ers GameDay Magazine in 2007, "as a running back, you never know when you're going to break [and] the most embarrassing thing to do is to get caught from behind." In 1958, he also led the 49ers with 15 kickoff returns for 356 yards for an average of 23.7 yards per return.

In 1959, Smith carried the ball 207 times for 1,036 yards to enter that elite group of NFL ball carriers who have gained more than 1,000 yards in a single season. In fact, his rushing total that year was second in the league only to NFL legend, Jim Brown. That same year he also scored 10 touchdowns, in only 14 regular season games. His 10 touchdowns in the 1959 season remains tied with six other 49ers, including Frank Gore and Joe Perry, for the most rushing touchdowns ever in single-season team history. For this tremendous season Smith was awarded The Len Eshmont Award, the 49ers oldest and most prestigious annual honor given each year to the 49er who best exemplifies the "inspirational and courageous play" of the award's namesake.

In his career with the 49ers, he rushed for 100-plus yards per game 12 times which ties him with Hugh McElhenny. In 1960 and 1963, he was selected to the NFL's Pro-Bowl. Smith led the 49ers in rushing for five consecutive seasons from 1959 – 1963 and led San Francisco in all-purpose yards from 1959 – 1961. He was part of the famed 'Alphabet Backfield' featuring Y.A. Tittle, R.C. Owens and C.R. Roberts. The humble, former 49ers star often downplayed his accomplishments and was once quoted as saying "When I read or hear about some of my accomplishments, I'm surprised myself."

Smith retired from football in 1966 but never lost his passion for the game. He scouted for the San Francisco 49ers for seven years post-retirement. He was an active member of the Northern California Chapter of the NFL Alumni Association, having played in and captained several charity golf tournaments, and often attended the 49ers Annual Alumni Weekend. He gave back to his community by mentoring young athletes and even coaching local Pop Warner football teams well into his senior years.

Born July 19, 1931 in Greenville, South Carolina, Smith attended Sterling High School and then went on to graduate from North Carolina A&T State University, a historically black college. In 1971, he was an inaugural member of the North Carolina A&T Sports Hall of Fame, alongside NBA and Golden State Warriors great Al Attles. Smith also went on to have a successful second career as a security executive at Sears, retiring in 1991.

Smith lived in Oakland's Laurel neighborhood and was an avid fisherman, gardener and jazz enthusiast. He is preceded in death by his wife, Mary, his mother Louise, his father J.D. Smith Sr. and his brother, James. Smith is succeeded by his daughter, Patricia, and two sons, Lonnie and David, as well as three grandchildren and three great-grandchildren.

Smith's family will say goodbye to their hero at San Francisco's Kezar Stadium in a private memorial. The family has asked that donations be made to the Foundation for the National Institutes of Health (FNIH) Sports and Health Research program in lieu of flowers or other gifts.