Alex Fernandez pitched for the Miami Hurricanes in college, and was selected as a first team All-American in 1989. The Chicago White Sox selected him with the fourth overall pick of the 1990 draft. Fernandez earned a callup to the Major Leagues later that year, joining the rotation in August and accruing a 5-5 record with a 3.80 ERA over 13 starts.

Over the next six seasons for Chicago, Fernandez made 184 starts (and two relief appearances). He posted an 18-9 record in 1993 and a 16-10 record in 1996. Altogether for the White Sox, Fernandez compiled a 79-63 record with a 3.78 ERA.

Fernandez signed a free agent contract to play with the Marlins prior to the 1997 season. In his first season with the club he posted a 17-12 record for the Marlins, helping them on their way to their first World Series title. He had a 3.59 ERA and a 1.187 WHIP, allowing fewer than eight hits per nine innings. Fernandez sustained a fully torn rotator cuff in losing Game 2 of the National League championship series against Atlanta.

After missing 1998 rehabilitating the injury, Fernandez rejoined the rotation in 1999, posting a 7-8 record and a 3.38 ERA and winning the NL Comeback Player of the Year award.

In three seasons total, Fernandez was 28-24 with a 3.59 ERA. He retired in 2001 after it became apparent that he would not be able to ever regain his pre-injury form.

He is currently a radio broadcaster, and is active in local politics in Miami Beach.