He played football at Ball High School,[1] where his role as a player was primarily as a blocking back.

As a result, opportunities to show his ability were limited; he did not manage 1,000 yards in his entire prep career and was only recruited by a handful of colleges.

[2] Alexander was recruited to Louisiana State University by running backs coach Jerry Stovall.

He later recalled that Stovall offered him trust and a real chance to be a big-time running back.

"[2] Alexander joined Hall of Fame coach Charles McClendon's LSU Tigers football team as a freshman in 1975.

[6] Alexander's workload dropped in his senior season in 1978, as the Tigers' offense became more balanced with fellow future LSU Athletic Hall of Famer David Woodley at quarterback.

"[5] He played his last game as a Tiger in the 1978 Liberty Bowl, in which he rushed for 133 yards on 24 carries in a 20–15 loss to Missouri.

"[8][4] In each of his final two seasons with the Tigers, Alexander was selected as a consensus All-American and earned All-SEC honors.

In their divisional round win against the Buffalo Bills, Alexander rushed for 72 yards and scored two touchdowns.