John C. McGinley felt a rush of pride as he watched his 9-year-old son Max escort his bride, Nichole Kessler, down the aisle during their intimate April 7 wedding outside their Malibu home. That is, until Max darted back toward the house. "I barked out orders to make sure Max was okay," recalls McGinley, 47, who plays the caustic Dr. Perry Cox on NBC's Scrubs. "You don't usually have the groom [yelling] at the altar, but I couldn't concentrate unless I knew Max was squared away." Turns out, Max, who has Down syndrome, was just fulfilling his best-man duties: He had gone to fetch Haley, one of the couple's two chocolate Labs, to join her mate Hudson alongside McGinley for the ceremony. Says Nichole, a 34-year-old Ashtanga yoga teacher from Santa Monica: "The sweetest thing was Max walking back with Haley, then sitting down, thinking, 'Okay, now I'm done.'"

Though Max eventually opted to hang out in the limo watching a DVD of The Wiggles during the rest of the ceremony, there were more surprises. "When the officiant greeted us, she said feel free to hug or whatever, so I gave my wife a big, fat kiss," says McGinley, who elicited happy murmurs from the crowd. "We didn't have to be in opposite corners until pronounced man and wife." The ceremony's spontaneous nature was perfect for the bride and groom, who met in 2003 when Max (McGinley's child with ex-wife Lauren Lambert) approached Kessler on the beach while McGinley was playing with his dogs. "We were completely open to however it was going to happen," says Nichole.

Later, when McGinley recited his vows in front of the almost 30 guests, "everyone was in tears," says Nichole. "Luckily I had tissue under my bouquet." Adds McGinley, a Millburn, N.J., native who got his big break as a tough sergeant in 1986's Platoon and recently appeared as a contractor in the family comedy Are We Done Yet?: "I start talking about Nichole and Max in the same sentence and I'm gone. It was the most private thing I've ever done in public."

During the reception in their living room, close family and friends such as John Cusack and John McEnroe feasted on sushi amid hydrangeas and orchids, and the bride and groom had their first dance to Ben Harper's "Waiting on an Angel." The two then hosted an impromptu jam session in the garage—including a serenade by Patty Smyth McEnroe, who chose a song she had written for husband John—before calling it a night at 3:30 a.m. "Everyone was overwhelmed with warmth and love," says Smyth McEnroe.

Following a May honeymoon in Italy, the McGinleys will return to L.A., where they're remodeling their home to make room for more kids, a lot more. "I want seven," proclaims McGinley, himself the second of five children. That's just fine with his new bride. Says Nichole: "Bring it on!"