In 1985, Alomar signed with the San Diego Padres at age 17, and joined the team's Class-A affiliate in Charleston. The following year, playing in Reno, he won the California League batting championship with a .346 average.
Alomar entered the major leagues in 1988 with the Padres, where he was an excellent fielder with speed and a solid bat. Defensively, he displayed excellent lateral range and a powerful arm, often making spectacular plays on ground balls hit deep in the hole between first and second base, and on balls hit up the middle well behind second base. He was an All-Star for the first time in 1990, as a reserve player for the National League.
"I don't think we'd have ever gone to the World Series in '92 if he didn't hit that home run off Eckersley in Oakland that day like 4:30 in the afternoon when you could hardly see at the plate [because of the shadows]."
On March 20, 2008, the Toronto Blue Jays announced that Alomar would be elevated to the Level of Excellence at Toronto's Rogers Centre, joining such Blue Jay legends as George Bell, Joe Carter, Tony Fernández and Cito Gaston. On April 4, 2008, Alomar's name and number were added to the Level of Excellence, along with team executive Paul Beeston, prior to the 2008 home opener. Alomar and Beeston were presented commissioned portraits at the ceremony.
On July 19, 2011, the Toronto Blue Jays announced that they would retire Alomar's number 12 soon after his official induction into the Baseball Hall of Fame. Roberto Alomar is the first player in Blue Jays franchise history to have this honor, which took place on July 31, 2011. Alomar is the first player to be inducted into the Hall of Fame depicted as a member of the Toronto Blue Jays.
In 1995, Alomar signed with the Baltimore Orioles at a time when Toronto was looking to rebuild, while Baltimore was improving into a pennant-contending team. In Baltimore, Alomar paired with Hall of Famer Cal Ripken, Jr. to form a formidable double-play combination. Alomar appeared in the playoffs in 1996 and 1997 for the Orioles, although the Orioles were defeated in the ALCS in both years.
On September 27, 1996, during a game against the Blue Jays, Alomar got into a heated argument over a called third strike with umpire John Hirschbeck and spat in his face. He defended himself by saying Hirschbeck had uttered a racial slur and that Hirschbeck had been bitter since one son had died of ALD and another had been recently diagnosed as well. Upon hearing this public disclosure of his private life, Hirschbeck had to be physically restrained from confronting Alomar in the players' locker room.
Alomar was suspended for the first five regular season games in 1997 and donated $50,000 to ALD research. Alomar and Hirschbeck settled their differences publicly and made apologies to each other on April 22, 1997, standing at home plate and shaking hands in front of the crowd before an Orioles game. Regarding the incident at his retirement, Alomar said, "That, to me, is over and done. It happened over nine years ago. We are now great friends. We have done some things with charity. God put us maybe in this situation for something. But I think people who know me, people who have had the chance to be with me on the same team, know what kind of person I am. Anything I ever did wrong, I would confront it and now it is OK."
On November 24, 1998, Alomar signed a 4-year contract with the Cleveland Indians, joining his brother, Sandy Jr. It was in Cleveland that Alomar had two of his finest seasons. In 1999 he hit .323/.422/.533 with 24 HRs, 120 RBI and 37 stolen bases, and in 2001 he batted .336/.415/.541 with 20 HRs, 100 RBI and 30 steals. Cleveland made the playoffs in 1999, losing in the ALDS to the Red Sox; in 2001 they again made the playoffs but lost to Seattle in the ALDS. Alomar finished third in MVP voting in 1999.
On the field, Alomar teamed with shortstopOmar Vizquel to form another decorated middle infield combination. In 2000, with Vizquel committing just three errors all season long, the entire Cleveland infield committed 34 errors—just one more than the record low set by the New York Mets infield the year before. Vizquel, Alomar and third basemanTravis Fryman each won the Gold Glove Award that season; the Vizquel-Alomar duo ultimately won three consecutive Gold Gloves together, becoming one of just eight shortstop-second baseman duos to have accomplished this feat in the same year.
In 2002, Alomar hit only .266/.331/.376 with 53 RBI and 73 runs scored, while falling apart defensively at second base. The Mets were puzzled by Alomar's mediocre play, which some attributed to his lack of comfort with being under the greater scrutiny of the New York fans and media. However, not even a midseason trade back to the American League to the Chicago White Sox in 2003 could revive Alomar from his funk. There was more misery ahead with the Arizona Diamondbacks in 2004, including a two-month disabled stint with a broken right hand. On August 5, Alomar returned to the White Sox, and hit just .263/.321/.392 in 56 games.
Alomar agreed to a one-year contract with the Tampa Bay Devil Rays for the 2005 season. However, on March 19, 2005, after a spring plagued by back and vision trouble, he decided to retire.
In a 17-year career, Alomar was a .300/.371/.443 hitter, with 210 home runs and 1,134 RBI in 2,379 games. At the time of his retirement, he was 51st all-time with 2,724 career hits.
2010 was Alomar's first year of Hall of Fame eligibility, but he missed induction by eight votes. His 73.7% of the vote was the highest percentage of votes in any player's first year on the ballot without being elected. Some baseball writers expressed shock that Alomar failed to get in on the first ballot, but many attributed the near-miss to sportswriters holding a grudge over the 1996 spitting incident with John Hirschbeck, including Alomar's brother Sandy and Hirschbeck himself. Alomar was elected to the Baseball Hall of Fame in his second year of eligibility with 90% of the vote (523 of 581 ballots cast). He is the third Puerto Rican in the Hall of Fame, after Roberto Clemente and Orlando Cepeda. On July 24, 2011, Alomar was formally inducted into the Baseball Hall of Fame in Cooperstown, New York as a member of the Toronto Blue Jays.
Alomar married Puerto Rican model Maripily Rivera on June 1, 2009. The next year, Rivera alleged that she had been victim of aggression from Alomar, and that she wanted to end the marriage. Rivera alleged she had been the victim of three separate incidents of domestic abuse where Alomar allegedly pushed her, and threatened her with a knife. Alomar denied the claims, and filed for divorce a few days later. He also alleged that Rivera had threatened to divorce him unless he gave her half ownership of his Tampa residence. In the midst of the scandal, rumors that Alomar was HIV-positive resurfaced, and Rivera sued him for allegedly exposing her to the virus, even though she had defended him previously when an ex-girlfriend made the same claims. The divorce was finalized on July 12, 2011 with a private settlement. The HIV claims remain unfounded.
Alomar resides in Toronto. On December 12, 2012, Alomar married Toronto native Kim Perks at the Art Gallery of Ontario. Their first daughter, Lourdes María, was born on April 11, 2014.