The couple married on Saturday in Montecito, California.
Pratt, 39, and the 29-year-old Schwarzenegger announced their engagement in January after quietly meeting for months ,
"Sweet Katherine, so happy you said yes!" the actor "Guardians of the Galaxy" wrote. "I'm excited to marry you, proud to live courageously in faith with you."
Schwarzenegger is the daughter of Arnold Schwarzenegger, the actor and former governor of California, and the radio journalist Maria Shriver, a niece of President John F. Kennedy. Pratt is also known for his roles in Parks and Recreation and Jurassic World.
Pratt has a son, Jack, with his ex-wife, actress Anna Faris. They separated in 2017 after eight years of marriage.
Faris said encouragingly on Pratt's Instagram post, "I'm happy for both of you!"
CNN has turned to Pratt's representative Comment.