He frequently described Lonegan's views as "extreme," noting his support of the shutdown and his opposition to immigration reform and federal aid in response to Hurricane Sandy.
Lonegan, the former mayor of Bogota, has described the election as a referendum on the national health-care law and Booker as President Obama's "rubber stamp."
He kept up his attack Friday, saying Booker hadn't created a "single job" and calling him "delusional" for thinking he had helped grow Newark's economy.
With another fiscal clash likely to erupt on Capitol Hill this month over raising the debt ceiling, Booker fired back at Lonegan, accusing him of supporting a "fringe group" in Washington that wants "to hijack the full faith and credit of the United States in order to push what they want."
Lonegan is a former state director of the national conservative group Americans for Prosperity, which has helped raise money for tea party candidates.
After the debate at 6ABC's Trenton studio, Booker told reporters that the Oct. 16 election was partly a referendum on the shutdown.
"Will New Jersey give an endorsement to the tea party and the hijacking of Americans' federal government, or will they say, enough of this, we want to send somebody to Washington that will bring people together? It couldn't be a clearer choice," Booker told reporters.
Asked about adopting a more negative tone than he has used for most of the campaign, Booker said that when he started his campaign, "we said this is a clear choice for New Jersey: whether it's a guy who literally ran New Jersey's tea party organization, who advocated making abortion illegal even in rape and incest, a person who believes very clearly that we shouldn't have Medicaid and Medicare . . . or somebody who has a track record for getting things done."
Booker has seen his lead in the race shrink from well over 20 points in some polls to 13 in the most recent Monmouth University survey, released this week. His campaign released his first TV attack ad the same day.
On Friday, he sometimes found himself on the defensive.
Lonegan accused him of "parading around California with Hollywood elite" and declared that New Jersey needs a "leader, not a tweeter," referring to Booker's prolific social media presence.
Booker acknowledged that he has traveled the country but said that has helped bring philanthropic investment to Newark.
When the Democrat touted what he described as Newark's exploding economic development, Lonegan said, "The only example of economic growth [in Newark] is the growth of Cory Booker's bank account."
The former Bogota mayor assailed Booker for collecting more than $1 million in speaking fees while serving as mayor, and also referred to the nearly $700,000 Booker has received since 2006 from a West Orange law firm he worked for as "kickbacks."
Booker received the money as part of his separation agreement with the firm, Trenk DiPasquale.
While he disclosed how much money he received from the firm in tax returns provided to reporters last month, he has not released the details of the agreement. He said his former law partners' private finances should not be made public.
"I said clearly the buyout was based solely on my stake in the business, period," Booker told reporters.
The firm has collected about $2 million in contracts with local agencies.
"This warrants being investigated," Lonegan said during the debate.
Lonegan said he would work to eliminate the federal Department of Education and would "like to be known as the man who dismantled the IRS as we know it."
On a rare occasion of agreement, both candidates said they oppose the spying on Americans by the National Security Agency.
The debate will be broadcast at 9:30 a.m. Sunday on 6ABC. The final debate will be held Wednesday at Rowan University.
Inquirer staff writer Jonathan Tamari contributed to this article.