Williams (right) on a later training ride with Lance Armstrong (left) and George Hincapie. (Olivier Morin/Agence France-Presse via Getty Images)

Like so many Americans, I was enormously entertained by Robin Williams. And he was just as good in person — on a bicycle.

Four years ago, Williams was an honored guest at a kickoff dinner for 18 wounded warriors participating in the 4,000-mile Sea to Shining Sea bike ride across America. The event had been organized by a nonprofit organization, World Team Sports (WTS), which runs athletic events for disabled Americans to give them the courage to lead normal lives. At the meal, Williams circulated among the disabled veterans, joking in his many voices with each of them and promising to ride with them.

At dusk the following day, a group of them gathered at the edge of San Francisco Bay for the traditional “wheel dip.” They would begin their ride with the back wheel in the Pacific and end it with their front wheel in the Atlantic. But that wasn’t so simple for these wounded warriors. It was a gusty grey evening, and the riders, wearing bright yellow foul-weather jackets, leaned into the wind, struggling across the sand toward the water. Some had been so injured that they had to be carried to the waterside. Others had lost a leg and were slowly making their way across the sand on prosthetics. A puzzling variety of standard bikes, machines propelled by hand cranks, and recumbent bikes were ridden, pulled or carried into the water. (I was there because of the admiration I developed for the men and women of the U.S. military when I served as presidential envoy to Iraq.)

The next morning, Williams made good on his promise to join the group at our first rest stop across the Bay Bridge in Sausalito. A little-known but vital part of Williams’s life had been his constant support for the men and women of the American military. For years, he had traveled to entertain U.S. troops in war zones overseas.

The author with Williams. (Courtesy of Paul Bremer)

We came across our first hills shortly after Williams joined us in Sausalito, enough to challenge some of the riders, especially those who had not been able to train on hills. So the group started to break into smaller bunches riding at different speeds. Williams rode up and down the line, cracking wise, giving color commentary and showcasing the instant repartee for which he was famous. He proved to be an experienced and engaging riding partner for the next 15 miles.

One of the wounded warriors was Chad Jukes. The Army staff sergeant lost a leg when his truck hit an antitank mine on convoy duty in northern Iraq. But could he ride a bike! Williams later told the press: “It’s amazing to be around these guys. They fly. I got my ass kicked by a guy on a bike with one leg!”

Williams left us at the next rest stop, in Fairfax. As he headed off to find a good cup of espresso, his parting shot was that the hills we had ridden were “nothing” compared with the ones we would hit just north of Fairfax, cheerfully adding that was why he was leaving us.

His brief ride with the wounded warriors showed the serious and loving side of this talented actor. His cheerful irreverence lighted their way for the remaining 64 days of their epic ride across America. He is missed by all of us who were touched, even briefly, by his wonderful humanity.