For all the fun and games, Holt, 64, an astrophysicist turned seven-term congressman, is also using his cred as an intellectual to make a case for being New Jersey's next U.S. senator. He says he is uniquely qualified to address issues such as climate change.
"The Senate could probably benefit from having some teachers," said Holt, a former professor at Swarthmore College. "It surely could benefit from having at least one scientist. I intend to be that scientist."
Holt did not make his way to Congress by rising through the state Democratic Party. His father, Rush Sr., was a state legislator in West Virginia and, at age 29, became the youngest person elected to the U.S. Senate by popular vote.
His mother was West Virginia's first woman to serve as secretary of state.
His father died while he was in the first grade, but for years afterward he ran into "complete strangers who recognized my name because my name is the same as my father's, and told me how much he meant to them, how much he helped them."
Just a few years ago, Holt said, he met someone at an environmental conference whose middle name was Rush.
"He was a little older than me," Holt recalled in a telephone interview. "He said: 'My father was a coal miner. He said to his dying day a coal miner never had a better friend than Rush Holt.' "
Such encounters helped Holt realize he could help people through politics.
But first he earned a Ph.D. in physics, and then won a patent for a solar-energy device that maintains "a correct density gradient in a nonconvecting solar pond," according to the U.S. Trademark and Patent Office.
Between 1989 and 1998, he was assistant director of the Princeton Plasma Physics Laboratory, the largest research facility at Princeton University and the largest such facility for alternative-energy research in New Jersey. His wife, Margaret Lancefield, is a physician.
Holt also worked for the State Department in arms-control negotiations.
"Probably when Cory was in grade school," Holt said impishly, referring to his rival Newark Mayor Cory Booker, he was "sitting across the table from the Soviet Union in Geneva, trying to hold them to the antiballistic missile treaty."
Polling has Booker as the front-runner in the Democratic primary to fill the seat vacated when Democratic Sen. Frank R. Lautenberg died in June.
In 1996, Holt ran for Congress and lost. Two years later, he won, famously running an ad that showed his Republican opponent, Michael Pappas, singing on the House floor in praise of Kenneth Starr, the independent counsel who investigated the Clinton administration. (Pappas set his song to the tune of "Twinkle, Twinkle, Little Star.")
After Holt won, his seventh-grade teacher reminded him that even as a boy Holt had subscriptions to the Washington Post and Scientific American.
"I guess I was going down two paths pretty early," Holt said of his interest in politics and science.
When he arrived in Washington, he met then-Rep. Vernon J. Ehlers (R., Mich.), the only other physicist in Congress. "Like physicists, we each made the calculation of, at this growth rate, by midcentury the entire House of Representatives would be physicists," Holt joked.
Since then he has waged campaigns for paper backups to electronic voting tallies, advocating for each machine to produce a paper record that could be used in recounts. He is also against the post-9/11 national security apparatus.
The latter issue gained traction recently after disclosures by Edward Snowden, a former National Security Agency contractor, showed the vast reach of the government's surveillance programs.
Holt is pushing to repeal the Patriot Act and FISA Amendments Act, which authorized the programs. Under the current "surveillance state," Holt says, Americans are regarded as "suspects first and citizens second."
Even though Holt can come off as a policy wonk, political observers say he is accessible to the average voter.
"Rush is an intellectual guy who connects with people," said Ben Dworkin, director of the Rebovich Institute for New Jersey Politics at Rider University.
"He's been very dedicated to constituent service, to helping people. Which is not uncommon for many congressmen, but it's something he's done well," Dworkin said.
Whether New Jersey voters will reward him for that with a Senate seat is another question. In the most recent Quinnipiac University poll, Holt received 8 percent of the vote, trailing Rep. Frank Pallone (10 percent) and Booker (52 percent). Assembly Speaker Sheila Oliver polled 3 percent.
Steve Lonegan and Alieta Eck are seeking the Republican nomination in the Aug. 13 primary. The special election is Oct. 16.
Holt is campaigning as the "true progressive" in the race - in the mold of Sen. Elizabeth Warren (D., Mass.), he said - and notes with pride that he has a 100 percent lifetime rating with the League of Conservation. "Nobody touches me on that," he said.
Pallone has suggested Holt may be too radical to get things done. At the first Democratic debate, in Trenton on Saturday, for example, Pallone said Holt's proposal for a single-payer health-care system "wasn't going to pass in the Congress."
In the interview, Holt was defiant. "Other candidates are talking 'progressive' this and 'progressive' that," he said. "I guess, maybe if I said 'liberal' instead of 'progressive,' they'd stop copying me on that. People are afraid to say 'liberal.' I'm not."
Monday: Republican Steve Lonegan.
Rush D. Holt Jr.
Education: B.A., Carleton College; master's and Ph.D., New York University
Family: Married, three children
Hometown: Hopewell Township, Mercer County
Experience: Seven-term congressman, former assistant director of Princeton Plasma Physics Laboratory
Key causes: Climate change, reining in the National Security Agency
Contact Andrew Seidman at 856-779-3846, firstname.lastname@example.org, or @AndrewSeidman on Twitter.
Inquirer staff writer Sean Carlin contributed to this article.