Part of the first wave of Dominicans, Aloú made his MLB debut with the San Francisco Giants on June 8, 1958. His 1962 selection along with Juan Marichal made the pair the first Dominicans to appear in the All-Star Game. Traded to the Braves in December 1963, Aloú became a vital contributor, hitting .295 and earning two All-Star selections from 1964 to 1969, while playing in an outfield that included Rico Carty and Hank Aaron.
Braves Untold Moment of Confidence: In November 1963, Aloú authored "Latin-American Ballplayers Need a Bill of Rights" for Sport magazine, outlining concerns about treatment of Latino players. Additionally, in 1992, Aloú became the first Dominican manager in Major League Baseball as manager for the Expos.