Without naming the "30 Rock" actor, the airline said on its Facebook page that an "extremely vocal customer" declined to turn off his phone when asked to do so by a flight attendant.
The customer then stood up "with the seat belt light still on for departure" and took his phone into a restroom, the company said.
"He slammed the lavatory door so hard, the cockpit crew heard it and became alarmed, even with the cockpit door closed and locked," the airline's post said.
The passenger also was "extremely rude to the crew, calling them inappropriate names and using offensive language."
On Twitter, American Airlines said its flight attendants followed federal safety regulations regarding electronic devices.
Baldwin boarded another American Airlines flight to New York after Tuesday's incident, but said he wouldn't fly with the airline again.
The actor's spokesman, Matthew Hiltzik, said Tuesday that before being booted from the flight, Baldwin was playing a game called "Words with Friends" while the plane idled at a gate at Los Angeles International Airport.
"He loves 'Words with Friends' so much that he was willing to leave a plane for it," Hiltzik said.
After the incident, Baldwin, a prolific Twitter user, took to the social media site to vent, saying a "flight attendant on American reamed me out 4 playing Words With Friends while we sat at the gate, not moving."
Baldwin tweeted that it would be his last flight with American, despite the fact that they show "30 Rock" for in-flight entertainment.
He mocked American Airlines flight attendants on Twitter, saying the airline is "where Catholic school gym teachers from the 1950's find jobs as flight attendants."
American Airlines spokesman Ed Martelle declined to comment, citing customer privacy concerns.
But the company said Wednesday on Facebook that "since an extremely vocal customer has publicly identified himself as being removed from an American Airlines flight on Tuesday, Dec. 6, we have elected to provide the actual facts of the matter," as well as the federal regulations.
The airline said the Federal Aviation Administration requires that all airlines have passengers turn off their cellphones and electronic devices for taxi-out and takeoff. The passenger in question declined to turn off his phone "when asked to do so at the appropriate time," the company said.
Airport police Sgt. Belinda Nettles said officers did not respond to the incident.
Baldwin called "Words With Friends" an "addicting" game. Players compete online to score the most points by building words with tiles on a Scrabble-like game board.
Baldwin plays the role of executive Jack Donaghy on "30 Rock" and played an amorous ex-husband to Meryl Streep in the 2009 romantic comedy "It's Complicated."
