Brooklyn called Olmo up to the major leagues in July 1943 and he debuted with the Dodgers on July 18, 1943. In 57 games, he batted.303 with four home runs and 37 RBI. He gained regular status in the next season, batting.258 with nine home runs and 85 RBI in 136 games. On May 18, 1945, Olmo became the second player in Major League history to hit a bases-loaded triple and a bases-loaded home run in the same game. He added a single for good measure, only failing to hit a double to complete the cycle. In that season, he led the league in triples and reached career-high numbers in batting average, home runs, RBI, doubles, stolen bases and games.
In 1946, Olmo was among a group of players enticed to play in the Mexican League with the promise of higher salaries; they were suspended by Baseball CommissionerHappy Chandler for jumping the major leagues. Two years later, Olmo was reinstated and he returned to the Dodgers, batting.305 in 1949 to help win the pennant.
In the 1949 World Series against the Yankees, Olmo became the first Puerto Rican to play in a World Series, as well as hit a home run and get three hits in a Series game. After two seasons, he was dealt to the Braves. He retired at the end of the 1951 season. In a six-year career, Olmo batted.281 with 29 home runs, 208 runs, 65 doubles, 25 triples, and 33 stolen bases in 462 games.
Olmo earned Caribbean Series MVP honors, during the 1951 edition played in Caracas, after batting.416 and three homers, while powering the Cangrejeros de Santurce to the championship. Olmo returned to the Series with Santurce in its 1955 title, and also played as a reinforcement for fourth-place Senadores de San Juan in 1952. Overall, Olmo posted a.303 average with three home runs and 13 RBI in three Caribbean Series.
Later years
Olmo was elected to the Caribbean Baseball Hall of Fame on February 6, 2004. His baseball career was featured in a 2008 American documentary titled "Beisbol", directed by Alan Swyer and narrated by Esai Morales, which covered the early influences and contributions of Hispanics in the game. The City ofArecibo honored Olmo by naming a stadium after him. Olmo had been suffering from Alzheimer's for more than a year. Olmo, who suffered from the complications of double pneumonia, died on April 28, 2017 in Santurce, San Juan, Puerto Rico.