The franchise traces back to an 1894 Western League club in Milwaukee and became a charter member of the American League in 1901. It relocated to St. Louis that same year as the Browns, where it spent five uneven decades, drawing modest crowds and reaching only a single World Series, in 1944. A Baltimore ownership group purchased the team in 1953 and moved it east for the 1954 season, rebranding it the Orioles after the city's original 19th-century National League club.

Under executives like Paul Richards and manager Earl Weaver, Baltimore built a pitching- and defense-oriented powerhouse through the 1960s and 1970s, winning three World Series and six pennants behind stars such as Brooks Robinson, Frank Robinson, and Jim Palmer. The team cooled after 1983, enduring a losing stretch through much of the 1990s and 2000s, with occasional playoff appearances led by Cal Ripken Jr. and Eddie Murray. A rebuild centered on young talent produced a 101-win division title in 2023, and David Rubenstein completed his purchase of the franchise from the Angelos family the following year.