Clark, who didn't compete in Iowa, told campaign workers in Manchester, N.H., that Kerry, a decorated former Navy officer, had a military background "but nobody in this race has got the kind of background I've got."
"It's one thing to be a hero as a junior officer. He's done that, I respect that," Clark said. "But I've got the military experience at the top as well as at the bottom."
He said he had no regrets about not competing in Iowa.
"When I got into the race with no money, no staff, no policy papers, it took time to assemble that. By that time, the window of opportunity in Iowa had closed."
In an indirect jab at Howard Dean, who came in a disappointing third in Iowa, Clark said "it says exactly what we've been saying in New Hampshire: that if you're going to run for president, you must have a positive message."
Clark has been saying that Dean's message is too negative.
As for his own campaign, Clark said: "It's the same race in that what I have to do is go out and communicate with the voters of New Hampshire."
Clark spent Monday evening at his Manchester headquarters, waiting to hear the results in Iowa. He planned to be there again Tuesday, talking to supporters and staff about the importance of the election.
Clark and Connecticut Sen. Joe Lieberman were the only major Democratic hopefuls to bypass the Iowa caucuses. Clark spent at least part of each day in the last week in New Hampshire.
Some polls showed he was closing on Dean's lead.