He also pursued supporters of Missouri Rep. Dick Gephardt, who bowed out of the campaign Tuesday after finishing a distant fourth in Iowa.
"I'm the only person in this race who can bring together people who are not Democrats and bring them into this party," Clark said in an interview with The Associated Press.
He continued to emphasize his nearly three decades of military service — compared to Kerry's service in the Vietnam War. Clark retired in 2000 with the rank of four-star general as supreme allied commander of NATO (search) forces in Europe.
"As president of the United States, I won't be a general. I'll be the president," Clark said.
Clark had bypassed Iowa to focus on contests in New Hampshire and beyond, and had been gaining on front-runner Howard Dean. But the Iowa caucus results Monday night changed the dynamics of the race.
The latest New Hampshire survey showed Dean, a former Vermont governor, still in the lead, but with Clark and Kerry now tied for second. Kerry had fallen to the back of the pack.
One of Clark's first moves Tuesday was to reach out to some of Gephardt's congressional backers, who not only would add Washington stature to the candidate who has never held elected office but would provide all-important delegates to the Democratic National Convention.
"General Clark called me this morning. I was very impressed with his campaign. I had a nice discussion with him and told him I'd like to talk to him at some future time," Rep. Steny Hoyer of Maryland, the No. 2 Democratic leader in the House and Gephardt backer, told reporters in Washington.
Clark also rallied supporters at his campaign headquarters in Manchester.
Asked by reporters about remarks Monday that he had been a general while Kerry was a Navy lieutenant, Clark said: "I was a patriot. I believed in service my country. I stayed with the military all the way through."
Kerry was a decorated Navy officer in Vietnam who later became an outspoken critic of that war. He is a four-term senator and member of the Senate Foreign Relations Committee.
In the AP interview, Clark said of Kerry: "I'm proud of John Kerry's service ... and I think he has a lot to be proud of. He pursued a different path than I did. I pursued a path of staying in public service in the United States armed forces."
Clark, who has accused the Bush administration of close ties to lobbyists and special interests, defended his own lobbying activities between his Army retirement and his decision last fall to run for president.
Disclosure documents released by Clark's campaign show he earned nearly $500,000 for nearly two years as a lobbyist for an Arkansas database firm.
The documents show he made presentations on behalf of Acxiom Corp. to federal officials, including Vice President Dick Cheney, then-Treasury Secretary Paul O'Neill and Transportation Secretary Norman Mineta. The small Little Rock-based company won a government contract for an air travelers screening program.
Clark said Acxiom was developing tools to help "keep this country safe" and that he tried to bring its work to the attention of the government.
"I was asked to do this by a company. I did ask them to pay me, because it was taking up a lot of time that could have been (spent) on other things," Clark told The AP.
In Washington, Hoyer told reporters he supported Gephardt "because Dick Gephardt is my friend ...I think he'd be a good president." He said he hadn't yet decided which way to throw his support.
Even so, Hoyer said, "I was impressed that Clark called so quickly this morning. ...There was no doubt in my mind why he was calling me."