As a child, Dustin Brown played handball, football, and judo before committing solely to tennis at the age of 8. Brown, who has dual citizenship (German and Jamaican) started his professional career in Jamaica after his family relocated there in August 1996. He competed in several junior tournaments that included the World Youth Cup in Mexico in 1998 and the Eddie Herr International Tournament in Florida in 2000. In 2002, he officially turned professional by competing in 24 consecutive Futures events. In 2003, Brown competed for the first time on the ATP Tour in Newport, Rhode Island.

Between November 9, 2009, and June 18, 2018, Brown finished in the Top 200 in the ATP Rankings every week. In November 2010, he broke through into the Top 100 for the first of three times in his career. Brown secured the No. 92 ranking after notable success in the ATP World Tour quarterfinals in Johannesburg, South Africa and Newport, Rhode Island. Brown earned his first ATP World Tour Challenger doubles title in Metz, France in 2010 with Rogier Wassen. In 2012, he had another ATP World Tour Challenger doubles win with partner Paul Hanley in Casablanca, Morocco. Brown competed at Wimbledon several times throughout his career and defeated former champions on two occasions; Lleyton Hewitt in 2013, and Rafael Nadal in 2015.

In 2014, Brown returned to a Top 100 finish at No. 89. He reached No. 64 in 2016. That same year, Brown won his 7th Challenger title in Manchester, Great Britain. He also represented Germany in the 2016 Rio Olympics. In 2017, Brown earned his fourth Top 10 win. He competed at Montpellier, France, the Challenger Semi-finals at both Irving, Texas and Surbiton, Great Britain, and the Challenger doubles final at Meerbusch, Germany. Brown advanced to the quarterfinals at the ATP World Tour 250 Event in Stuttgart, Germany in 2019. He also won a Challenger doubles title at Noumea, New Caledonia with partner Donald Young and advanced to the Challenger doubles final in Bergamo, Italy with Tomislav Brkić that year.

Brown announced his retirement from professional tennis in 2024 due to persistent injuries.