His next task - unseating Fitzpatrick, the early favorite among most national forecasting services - will come in the most closely contested district in the region, one that includes Bucks and a sliver of Montgomery County and has been long coveted by national Democrats.
For Naughton, also a first-time candidate, such a loss was bittersweet.
"Is it better to lose by 6,000 [votes]? I don't know," she said late Tuesday. "I've lost by 600. I've never done this before."
Naughton said she offered Strouse her full support. "It's never easy to unseat an incumbent," she said about Strouse's race against Fitzpatrick. "But he's clearly shown he's willing to put time and effort into it."
Strouse, who moved to Bucks last year, quickly earned the backing of the Democratic Congressional Campaign Committee after announcing his candidacy.
But the local party opted for an open primary between Strouse and Naughton, who runs her family printing business, hoping it would attract more attention for each candidate.
National Democrats won the seat in 2006 and 2008.
For the most part, both candidates refrained from taking shots at one another - in two debates last month, they saved attack lines for Fitzpatrick, and a television ad from Strouse focused on his biography without mentioning Naughton.
But as the primary neared, both Strouse and Naughton sent mailers to voters attempting to disparage their Democratic counterpart.
And last week, Naughton went on the offensive after an Inquirer report detailed how Strouse's parents - after donating the maximum allowed to their son's campaign - contributed to numerous DCCC-backed candidates across the country last year. Days before or after those contributions, parents of at least four candidates sent nearly identical contributions to Strouse's campaign.
Strouse's campaign categorized Naughton's assertions as "desperate."
Joyce Retzler, 58, of Bristol Township, voted for Naughton, she said, because Bucks County was due for a female representative.
"I just went from my gut," said Retzler, who recently lost her job when the auto-parts business went under. "Women have a lot more compassion. They feel for people more."
Tom Jakubowski, 61, of Bensalem, said he was supporting Strouse because of his military background and the perspective he believed a veteran could bring to Washington.
Said Jakubowski: "I think he deserves a shot.