The 51-year-old's resume tells the story of a baseball lifer who has been an integral part of the sport for three decades.
Here are five things to know about Ng (pronounced Ang).
She's not only the first female GM in MLB history, but the first Chinese American GM
Ng's father, Jin, who died when she was 11, was American-born and of Chinese descent. Her mother, Virginia, was born in Thailand and of Thai Chinese descent. While Ng's qualifications were clear, it took until Friday for her to break two significant barriers. Systemic racism in the sport reared its ugly head in a very public way in 2003, when New York Mets special assistant Bill Singer directed racist remarks at Ng during the general managers meetings in Arizona. At the time, Ng was the Los Angeles Dodgers' assistant general manager; Singer was fired for mocking her ancestry.
Adding to what makes her hiring so historic: She becomes not only the first female GM in MLB history, but the first for any team in a major American men's professional sports league.
Early in her career, she went up against superagent Scott Boras -- and won
After graduating from the University of Chicago in 1990, she was hired as an intern by the Chicago White Sox. She began with typical entry-level tasks, like operating the radar gun and charting pitches. By 1996, she had developed a reputation as a negotiator and moved up the chain in the organization. That year, she became the first woman to present -- and then win -- an arbitration case, facing off with Boras over pitcher Alex Fernandez.
She grew up a Yankees fan in Queens
Ng was born in Indianapolis, but attended elementary school in Queens and high school in New Jersey. She learned the game by playing stickball in the street and was later a star shortstop on the University of Chicago's softball team. Her favorite player growing up? Yankees catcher and captain Thurman Munson. As Ng told ESPN in 2015 she rooted for Munson because "he was an incredibly gritty player" and she still has the scrapbooks she made from newspaper clippings about Munson's untimely death in a 1979 plane crash.
Her relationship with Marlins CEO Derek Jeter goes back more than 20 years
Yankees GM Brian Cashman hired Ng as an assistant GM in 1998, when she was just 29 years old. During her four years with the club, the Yankees won three World Series titles and four American League pennants. Among her accomplishments: Successfully negotiating contracts with Paul O'Neill, Mariano Rivera and then-shortstop Derek Jeter.
"I was truly excited for Kim when I learned that she had been named general manager of the Miami Marlins," Cashman said in a statement Friday. "It is wonderful seeing people accomplish their stated goals, and this has been a dream of hers for as long as I've known her. As assistant general manager with the Yankees, she was indispensable to me when I first began my tenure as the GM. Kim was a tireless and dedicated executive back then, and in the ensuing years, she has ceaselessly added to her skill set to maximize her talent. She will provide the Marlins with vast experience and institutional knowledge along with a calm demeanor and an amazing ability to connect with others - all of which will serve her well in her new leadership role as head of baseball operations. I offer my congratulations to her and to the Marlins organization."
She's been in the conversation for GM jobs for more than a decade
Before finally landing the gig in Miami, Ng had interviewed for an MLB GM job more than a half-dozen times since 2005, including with the Phillies, Mets, Giants, Dodgers, Mariners and Padres. And whenever the question, "Who will be the first female GM in MLB history?" was asked, her name typically was on the top of the list. But though she wanted the job, being first was never how she defined herself amid her many accomplishments in the sport.
"At the end of the day, if this doesn't happen, I'm not going to see it as, 'My career was a failure,'" she told The University of Chicago Magazine. "That might be other peoples' take, but that's not mine. I know how hard it is. I know about all the guys who didn't even get an interview who probably should have had an interview. I've been very fortunate. I've worked extraordinarily hard to get where I am. If I don't end up becoming a general manager, that's just the luck of the draw. I've had a great career regardless."