Bellino has umpired Major League Baseball games since the 2008 season, he was promoted to the full-time MLB staff in . Bellino had previously umpired in the New York-Penn, Midwest, Florida State, Eastern, Pacific Coast and International leagues. Bellino worked his first major league game between the Orioles and Cubs at Wrigley Field in June, 2008. Bellino also worked in the Arizona Instructional League, Hawaii Winter League, Arizona Fall League, and Puerto Rico Winter League. Dan has been assigned to divisional post season assignments each year from 2014 to 2018, and was selected to work the opening series for the 2012 season in Tokyo between the Seattle Mariners and the Oakland Athletics. Additionally, Bellino worked his first MLB All-Star Game in 2016 at Petco Park in San Diego, serving as the right field umpire, and has worked in the World Baseball Classic in Puerto Rico (2013) and Guadalajara (2017).