Michael Glen Dunn, known in the baseball world as Mike Dunn, made his presence felt on the mound as a left-handed relief pitcher. Born on May 23, 1985, in Farmington, New Mexico, Dunn's journey to Major League Baseball (MLB) began when he was drafted by the New York Yankees in the 33rd round of the 2004 MLB Draft. His early career saw him honing his skills in the minor leagues, where he developed the fastball and slider combination that would become his trademark.

Dunn's MLB debut came on September 4, 2009, with the Yankees. Although his time with the team was brief, it marked the beginning of a decade-long career in the majors. Following his stint with the Yankees, Dunn was traded to the Atlanta Braves in December 2009 as part of a deal that sent Javier Vázquez to New York. During his time with the Braves in 2010, Dunn appeared in 25 games, posting a 1-0 record with a 1.89 ERA, showcasing his potential as a reliable bullpen arm.

In November 2010, Dunn was traded to the Florida Marlins (later the Miami Marlins) as part of a multi-player deal. It was with the Marlins that Dunn found stability and spent the majority of his career. From 2011 to 2016, he became a mainstay in the Marlins' bullpen, known for his ability to handle high-pressure situations and face tough left-handed hitters. Over these six seasons, Dunn appeared in 405 games, recording a 3.59 ERA and striking out 349 batters in 328 innings pitched. His durability and consistency were valuable assets to the Marlins' pitching staff.

Dunn's tenure with the Marlins ended after the 2016 season when he signed a three-year contract with the Colorado Rockies. His time in Colorado, however, was marred by injuries. In 2017, he appeared in 68 games, but his performance was inconsistent, resulting in a 4.47 ERA. The following seasons saw Dunn struggle with shoulder issues, limiting his appearances and effectiveness on the mound. In 2018, he was limited to just 23 games, and in 2019, he pitched in only 28 games before being released by the Rockies in August.

Throughout his career, Dunn was known for his fastball, which could reach the mid-90s, and his sharp slider, which he used effectively against left-handed batters. His ability to pitch in high-leverage situations made him a valuable asset in the bullpen, particularly during his years with the Marlins. Despite the challenges he faced in the latter part of his career, Dunn's perseverance and skill earned him respect among teammates and opponents alike.

After his release from the Rockies, Dunn did not return to MLB, marking the end of his professional playing career.