Matt Whiteside's journey through professional baseball began when he was drafted by the Texas Rangers in the 12th round of the 1990 MLB Draft. A right-handed pitcher, Whiteside made his Major League debut with the Rangers on April 9, 1992. During his time with Texas, he primarily served as a relief pitcher, appearing in various roles out of the bullpen.

Whiteside's tenure with the Rangers lasted until 1994, after which he spent time with several other Major League teams. In 1995, he joined the Philadelphia Phillies, where he continued to pitch in relief. His stint with the Phillies was brief, and he moved on to the San Diego Padres in 1996. Whiteside's role remained consistent as a reliever, providing depth to the pitching staff.

The following year, Whiteside signed with the Atlanta Braves, although he did not appear in any Major League games for them. Instead, he spent the season in the minor leagues, honing his skills and awaiting another opportunity in the majors. In 1998, he found his way back to the big leagues with the Toronto Blue Jays. His time with the Blue Jays was short-lived, and he returned to the minors after the season.

Whiteside continued to pursue his baseball career, playing in the minor leagues and independent leagues. In 2001, he signed with the Pittsburgh Pirates organization, but once again, his appearances were limited to the minor leagues. Despite the challenges of maintaining a spot on a Major League roster, Whiteside persevered, showcasing his abilities in various minor league teams.

In 2005, Whiteside made a brief return to the Major Leagues with the Cincinnati Reds. This marked the final chapter of his Major League career, as he retired from professional baseball shortly thereafter. Throughout his career, Whiteside demonstrated adaptability and perseverance, navigating the ups and downs of professional baseball.