This Orioles team stayed mediocre for the first few years of its existence, but after the arrival of Jack Dunn (1872–1928), as manager, it won the Eastern League pennant in 1908.

Featuring another future Hall-of-Fame pitcher in Lefty Grove, the Orioles improved on that in 1920 by winning 110 games, including the last 25 of the season.

Even after relocating several blocks northwest to the old 1922 football bowl of Municipal Stadium on 33rd Street Boulevard (also known as "Baltimore Stadium"), the team seemed to have a hard time recovering from that loss, playing lackluster ball through the rest of the season and losing their last game, only to strangely "back into the championship" when the second place team, the Newark Bears, also lost their recent games.

The Orioles, under manager Alphonse "Tommy" Thomas, went on to win the "Junior World Series" that year, four games to two, against Louisville.

Six years later, with the shackles of war-time baseball cast off, in 1950, under manager Nick Cullop, Baltimore won the league championship again, only to lose the "Junior World Series" to the Columbus Red Birds of Ohio, four games to one.