Austin Kearns, a right-handed outfielder, began his Major League Baseball career with the Cincinnati Reds. Drafted seventh overall in the 1998 MLB Draft, Kearns quickly rose through the minor league ranks, making his MLB debut on April 17, 2002. His rookie season was marked by a strong performance, as he hit .315 with 13 home runs and 56 RBIs in just 107 games, earning him a third-place finish in the National League Rookie of the Year voting.

Kearns' early years with the Reds showcased his potential as a power hitter and a reliable defensive player. In 2003, he continued to demonstrate his abilities, although his season was interrupted by injuries, limiting him to 82 games. Despite these setbacks, he managed to hit 15 home runs and maintain a batting average of .264. Injuries would become a recurring theme in Kearns' career, often hindering his ability to play a full season.

In 2006, Kearns was traded to the Washington Nationals in a multi-player deal. This move provided him with a fresh start, and he quickly became a regular fixture in the Nationals' lineup. During his time in Washington, Kearns was known for his strong arm in the outfield and his ability to get on base. His best season with the Nationals came in 2007, when he played in 161 games, hit 16 home runs, and drove in 74 runs. However, his batting average dipped to .266, and he struggled with consistency at the plate.

Kearns' tenure with the Nationals lasted until 2009, after which he signed a one-year contract with the Cleveland Indians. In Cleveland, he experienced a resurgence, hitting .272 with 8 home runs and 42 RBIs in 84 games during the first half of the 2010 season. His performance caught the attention of the New York Yankees, who acquired him in a trade deadline deal. Kearns provided depth for the Yankees' outfield, though his offensive numbers declined during his stint in New York.

Following his time with the Yankees, Kearns returned to the Indians for the 2011 season. However, his performance was less impressive, as he struggled to find his rhythm at the plate, hitting just .200 with 2 home runs in 57 games. Despite these challenges, Kearns continued to find opportunities in the major leagues, signing with the Miami Marlins in 2012. With the Marlins, he served as a veteran presence and a part-time player, appearing in 87 games and hitting .245 with 4 home runs.

Kearns re-signed with the Marlins for the 2013 season, but his playing time was limited due to injuries and the emergence of younger players. He appeared in only 19 games, marking the end of his major league career. Over his 12-year career, Kearns played in 1,153 games, hit 121 home runs, and recorded a .253 batting average.

Throughout his career, Kearns was known for his strong defensive skills, particularly his arm strength in the outfield, and his ability to draw walks.