In 2003, Moylan played for the Macoto Gida of the Chinese Professional Baseball League, registering a 3.00 ERA in four games.

His 96 miles per hour (154 km/h) fastball enabled him to strike out established major-leaguers Bobby Abreu, Marco Scutaro, Ramón Hernández and Magglio Ordóñez.

Based on his performance in this tournament, Moylan was invited to participate in spring training prior to the 2006 season with the Atlanta Braves.

On 11 April 2006, Moylan was called up to the Braves to replace Joey Devine in the bullpen and he made his MLB debut the following day, pitching one scoreless inning against the Philadelphia Phillies; however he was later sent back to the Richmond club.

At the end of spring training in 2007, Moylan was again assigned to Richmond, but he was quickly called up on 14 April due to the injury of pitcher Chad Paronto.

Moylan exceeded rehabilitation expectations and was declared fit to pitch during the Braves' 2009 Spring Training camp in Orlando, Florida.

After a few shaky appearances in April, Moylan began to find more consistency during May, settling into his role as the team's primary 7th inning specialist.

[6] Moylan returned to the Braves on 3 September 2011, but after six appearances, he was diagnosed with torn rotator cuff and labrum in his pitching shoulder.

Although he was initially expected to miss most or possibly all of 2012,[7] it was later estimated that he would need a six-month recovery period, allowing him to be ready for spring training in 2012.

[8] While with the Braves, Moylan gained a reputation as a fan favourite through his embrace of Twitter and his sense of humor, even posting a link to a photo of himself in a dress stating he was wearing it to the ESPYs.

On 16 January 2013, the Los Angeles Dodgers signed Moylan to a minor-league deal and he was assigned to the AAA Albuquerque Isotopes.

[13] On 5 March 2015 Moylan signed a two-year minor league deal with the Braves that included a spring training invite for 2016.