The 56-year-old Frasier star married his 29-year-old fiancé at New York City's Longacre Theater, where Grammer just finished his run in the Broadway musical La Cage Aux Folles.
Missing from the festivities was ex-wife Camille Grammer. Divorce papers were filed in a Los Angeles court on Feb. 10. Camille had previously asked the judge to deny Kelsey's request to dissolve the couple's marriage.
This is the fourth marriage for Kelsey, and the first for Walsh.