Ben Affleck's character's name comes from the first name of the popular DC superhero, Oliver 'Ollie' Queen/Green Arrow. Kevin Smith wrote 15 issues of Green Arrow just prior to working on Jersey Girl (2004).
Kevin Smith's commitment to Jersey Girl (2004) has been so demanding that he couldn't finish two Marvel comic books that he began. The first being "Daredevil: The Target", which didn't get past issue one. The second, being "Spider-Man and the Black Cat", which he promoted on an episode of the Jay Leno show but only got to issue three, leaving the readers in suspense as to the Black Cat's fate at the edge of issue three's cliffhanger ending. Smith did go back to complete the final 3 issues of the book 3 years later
Following the failure of Gigli (2003), Miramax removed all images of Jennifer Lopez from all promotional spots, out of fear that people would think it was another Ben Affleck-Jennifer Lopez vehicle. The release date for "Jersey Girl" was pushed back from autumn 2003 to early 2004 and the studio also attempted to play down the presence of Lopez's character, Gertrude, in the movie, which included a public revelation about her character's fate.
A special premiere was held at Paulsboro High School where a number of scenes in the movie was filmed. Smith liked the town so much and the town liked him, a street leading out of the school was named Kevin Smith Way.
When the script was first written it was a number from "Cats" that Gertie was to perform at her school play, but the show closed before filming started. It was replaced with a number from "Sweeney Todd: The Demon Barber of Fleet Street".
One of the rooms of the house has a wall of framed black-and-white photographs. Some of these are young photos of George Carlin himself, most noticeably a bust shot of him dressed for the Air Force, which he had joined at the age of 18.
While generally not considered part of Kevin Smith's so-called "Askewniverse" series, the film does have one potential tie-in character/actor: Betty Aberlin portrays an unnamed nun in both this film and Dogma (1999), her role being substantially larger in this film.
The emergency room that Ollie and Gertie went to deliver the baby is the emergency room of the now closed, Mercy Community Hospital in Havertown, PA, which, by the way, never had that many staff members working in it when it was open. It also never had maternity department. It's obvious that it is not in the NYC area by the fact that it has only 6 beds, 4 curtains and 2 rooms.