Both Broadway veterans, the two met in 2007 and got engaged this past New Year's while on vacation in Puerto Rico.
"Well that was just the best day ever #SadieSadiemarriedlady," McDonald, 42, Tweeted late Saturday.
This is the second marriage for McDonald, 42, and Swenson, 38, who have children with their former spouses. McDonald is mother to one daughter, Zoe Madeline, 11, and Swenson is father to two sons, Bridger, 11, and Sawyer, 8. The couple tells PEOPLE that they look forward to their new life together as husband, wife and "wee posse of three."
After four seasons playing Dr. Naomi Bennett on ABC's hit medical drama Private Practice, McDonald returned to Broadway in January of this year, starring in the Tony Award-winning Broadway revival of The Gershwins' Porgy and Bess. The show recently completed a historic 322-performance run. For her portrayal of Bess, the Juilliard-trained singer and actress won a record-tying fifth Tony, placing her in the illustrious company of Broadway legends Julie Harris and Angela Lansbury as the only people in Tony history to win five performance awards.
Will Swenson was most recently seen as Tick in the critically acclaimed Broadway production of Priscilla Queen of the Desert. He is currently in rehearsals for Manhattan Theatre Club's Murder Ballad, a new rock musical opening on Nov. 15 at City Center Stage II.