The pair married in Broadway's Longacre Theatre, where Grammer recently appeared in La Cage aux Folles.
The ceremony was attended by Jude, Grammer's 5-year-old son from his marriage to ex-wife Camille. However, Us Magazine reports that his 8-year-old daughter Mason was not at the wedding.
Walsh, 29, is Grammer's fourth wife. The actor finalised his divorce from Camille earlier this month.