The couple met in summer 2011 and became engaged this April.
According to E! News, the 54-year-old actor and 28-year-old yoga instructor exchanged vows in front of family and friends at the Basilica of St. Patrick's Old Cathedral in Manhattan.
"Hilaria Thomas and Alec Baldwin were married this evening... in New York City," tweeted Matthew Hiltzik, a friend of the pair.
"Alec warmly [received] congratulations from well-wishing fans on his way into the service."
People magazine reports that the bride wore a silk Amsale gown, while the groom donned a tuxedo from Tom Ford.
Baldwin's 16-year-old daughter with ex-wife Kim Basinger, Ireland Baldwin, witnessed the ceremony, as well as fellow comics Jimmy Fallon and Tina Fey. Woody Allen, SNL and 30 Rock producer Lorne Michaels and Alec's brothers Billy and Stephen were also said to be in attendance.
Baldwin recently signed up to appear in the revival of Broadway show Orphans, which is due to open next year. He can currently be seen in Woody Allen's To Rome With Love, which was released in selected US cinemas last month.
Watch the trailer for To Rome With Love below: