Jamaal Williams was born on April 3, 1995, in Rialto, California. Williams was named as the league MVP as a senior at Summit High School in Fontana, California, as he led his team to the CIF division title. Williams ran for 1,252 yards and 22 touchdowns as a senior, as he won all-league honors and first-team All-CIF recognition. Williams earned a scholarship to BYU, where he played four years for the Cougars. In his career at BYU, Williams rushed for 3,901 yards and 35 touchdowns, plus caught 60 passes for 567 yards and one more score.
In the 2017 NFL draft, the 6’0”, 213-pound Williams was drafted in the fourth round by the Green Bay Packers. As a rookie in 2017, Williams