Delvin Williams was born in Houston, Texas in 1951, and attended college at the University of Kansas. He was drafted in the second round of the 1974 NFL Draft by the San Francisco 49ers.
As a rookie, Williams was used sparingly, gaining 201 yards on 36 carries, including a 71 yard touchdown run on October 27th against the Oakland Raiders in a 35-24 loss.
In 1975, Williams saw his role grow within the organization, leading the 49ers with 631 yards on only 117 carries, good for a 5.4 yard average, twice gaining over 100 yards in a game. He also caught 34 passes and scored a total of four touchdowns for the 5-9 team.
Williams enjoyed his first 1,000 yard season with the 49ers in 1976, gaining an NFL third best total of 1,203 yards on 248 carries. He had five games of 100 yards or more, scoring a total of nine touchdowns that season, and was invited to his first Pro Bowl following the season.
In 1977, Williams gained over 100 yards three times, and finished with 931 yards on 268 carries. To make room for incoming running back O.J. Simpson, Williams was traded to the Miami Dolphins following the season for wide receiver Freddie Solomon. Simpson would not produce for the 49ers as thought, leading the team in rushing with less than 600 yards in 1978, and the team finished 2-14. Williams, however, was just getting started.
In his first year with the Dolphins, Williams was recognized with first team All-NFL honors by several media outlets, including the Associated Press. He gained 1,258 yards, good for fourth best in the NFL, on 272 carries, and five times gained at least 100 yards. He finished the season with eight touchdowns.
1979 saw Williams gain 703 yards on 184 rushes, as he split carries with returning legend Larry Csonka. He again led the team in rushing in 1980, with 671 yards on 187 carries, scoring two touchdowns.
In 1981, Williams joined the Green Bay Packers, but did not see any significant playing time with the club. In 45 games over three seasons with Miami, Williams gained a total of 2,632 yards on 643 carries, scoring 13 touchdowns. He also caught 70 passes for 574 yards and another touchdown.