Peter Parker's character design was originally intended to resemble the one seen in the comics. This design, however, was switched towards the final production of the show to a design clearly patterned after Nicholas Hammond though younger and more contemporary than Peter Parker seemed to look in a lot of the comics and wearing a short-sleeved rugby shirt. The crew ended up revising Peter's wardrobe in season two to make it better than the design they started with and give Peter a cooler look, as well as better hide his Spider-Man costume under his clothes.
Fox aired episode 1.01 "Night of the Lizard", months before the other Season 1 episodes as a special sneak preview.
Virtually the entire Marvel Universe was available to be used in this series.
Episode 1.13 "Day of the Chameleon", was aired in primetime on Fox, along with the third season finale of X-Men.
Debra Whitman makes her animated debut in this series.
Anastasia Hardy, the mother of Felicia Hardy, makes her animated debut in this series.
Alistair Smythe and his father Spencer Smythe make their animated debut in this series.
Harry Osborn makes his first animated appearance in this series. Though he never appeared in any prior Marvel shows, Harry was mentioned as Peter Parker's friend and roommate in 1981's "Spider-Man" animated series.
The "Six Arms Saga" from Amazing Spider-Man #100-102 was adapted for the "Neogenic Nightmare" storyline in Season 2. Though in this series, Peter's transformation was not caused by his attempts to remove his powers, but a result of his body mutating further from the original spider-bite.
John Semper got the idea to give the wealthy Armored Spider-Man from a parallel universe a Giant Robot came from the Japanese Spider-Man series, "Supaidâman" (1978).
Spiderman's associates Detective Terri Lee and Dr. Mariah Crawford were created specifically for this series.
John Jameson, the astronaut son of J. Jonah Jameson, makes his animated debut.
The backgrounds seen during a "Spider Sense" are a nod to the backgrounds used during the Ralph Bakshi era of the 1960's Spider-Man (1967) cartoon.
This is the first series to refer to the Connors family (Curt Connors, Margaret Connors, and Billy Connors) by their correct surname. In the 1960's "Spider-Man" cartoon the family is named "Conner". In season one's "Night of the Lizard" of "Spider-Man", though, the sign on the Connors home is mistakenly spelled "CONNERS".
In the comics, the Insidious Six are called the Sinister Six. The Fox Kids network had the name changed to "Insidious Six" because they thought the name "Sinister Six" sounded too menacing for a cartoon series for children.
Of the six members of the Insidious Six, only two of the members of the Sinister Six (the team from the Spider-Man comics that the Insidious Six are based on) make it into the team's roster: Doctor Octopus and Mysterio. Shocker, Chameleon, Scorpion and the Rhino substitute for the Sinister Six's absent members - Sandman (who doesn't appear in the series at all), Electro (named Max Dillon in the comics, but shows up in Season Five as Rhienholt Kragov, the step-brother of the Chameleon and the Red Skull's son for the series), the Vulture (who joins the Six to take Mysterio's place in season five) and Kraven the Hunter (the step-brother of the Chameleon in the comics).
Electro was supposed to appear in the series before his eventual debut in Season Five's "Six Forgotten Warriors" story arc. Electro was held back from appearing, however, because James Cameron tried for years to write and direct a theatrical "Spider-Man" movie with Sandman as the secondary villain and Electro as the main villain. The legal rights to the "Spider-Man" movie went into limbo for over a decade, with Electro and Sandman still intended to be the villains. However, writer John Semper was able to include him into the series, but not as Max Dillon and he was not an American. Instead, a new character was created for the show. On the animated series, Electro was really Rheinholt Schmidt, the second Red Skull who was the original Skull's son and the step-brother of the Chameleon, none of which was actually in the comics. Rheinholt's real last name was never revealed on the show, though he went by the assumed name of Rheinholt Kragov while the Chief of the Russian Police in the "Six Forgotten Warriors" episodes in season five, and the Red Skull later uses the Doomsday device to turn his own son into the ultimate weapon, Electro.
William Baker, a.k.a. the Sandman, was supposed to appear in several episodes of the cartoon series, but was held back from appearing because James Cameron tried for years to write and direct a theatrical "Spider-Man" movie with Sandman and Electro as the villains. However, the legal rights to the movie went into limbo for over a decade and the character is the only major classic Spider-Man villain to have never appeared on the series.
The entire X-Men team were supposed to be included in "Secret Wars", but they were ultimately cut because, according to writer John Semper, it would have been too expensive to get the cast to fly from Canada to Los Angeles to record their dialog for the show. However, Storm was the only one able to appear because Iona Morris was the only X-Men cast member based in California.
John Semper admitted in an on-line interview that a storyline with Dormammu and Mysterio was originally planned. However, plans for this were scrapped when the voice of Mysterio, Gregg Berger, had left the series.
According to an on-line interview with John Semper, the reason that the Hobgoblin was added to the show in Season One before the Green Goblin was that plans for the character were being done before he arrived by writers and crew members that were no longer involved. By that time, the Hobgoblin had been made into an action figure for the animated series that was going to be released, so Semper admitted they had to let him stay on the series.
The cast of the Fox Kids cartoon X-Men cross over as their respected roles (episode 2.04 "Neogenic Nightmare Chapter 4: The Mutant Agenda")
The character Lewald is named after the story editor on the X-Men cartoon (Eric Lewald) (episode 2.04 "Neogenic Nightmare Chapter 4: The Mutant Agenda").
The X-Men voice actors had to be flown to L.A. from Canada, making this and the next episode very expensive to make (episode 2.04 "Neogenic Nightmare Chapter 4: The Mutant Agenda").
At the end of episode 3.01 "Sins of the Fathers Chapter 1: Doctor Strange", Doctor Strange tells Wong that he senses someone whose powers dwarf even his. We see that they are being watched by Madame Web, voiced by Joan Lee, the wife of Spider-Man's co-creator Stan Lee.
Episode 3.02 "Sins of the Fathers Chapter 2: Make a Wish along with episode 3.03 "Sins of the Fathers Chapter 3: Attack of the Octobot," episode 3.04 "Sins of the Fathers Chapter 4: Enter the Green Goblin," and episode 3.05 "Sins of the Fathers Chapter 5: The Rocket Racer," were released on video and DVD called "The Ultimate Villain Showdown" during the run of the Spider-Man movie.
Spider-Man only throws a punch three times in this series, once at the Scorpion in the Season 2 finale ("The Final Nightmare"), then again at the Spot in Season 3 ("The Spot") and once again at the Green Goblin ("Turning Point"). Other than those episodes, Spider-Man never punches his enemies, nor does anyone fire a single gun that doesn't fire a beam or projectile instead of bullets.
During the middle of the 5th season of Spider-Man, Fox Kids was thinking about keeping the series on a little longer but then Marvel and Fox Kids decided to ended after 5 seasons and show a 2-hour series finale. The reason why Fox Kids and Marvel canceled the show had nothing to do with ratings. The reason was the fact that Saban Entertainment wanted to Marvel's animation for their cartoon series. So after Spider-Man was canceled, Marvel and Saban made another cartoon that continued where Spider-Man left off, the series was called Spider-Man: Unlimited.
By the time the Spider-man series came on, there was a lot of censorship at Fox and they were very nervous about violence. Fox had very strict rules about violence and language in the show, including: "When Spider-Man lands on the rooftop, be sure that he doesn't harm any pigeons."
Dr. Robert Bruce Banner/The Incredible Hulk was actually supposed to make several guest appearances on the show, most notably the 3-part "Secret Wars" storyline in season five. However, the Hulk was unable to appear on the series in seasons four and five of "Spider-Man" because of "The Incredible Hulk" animated series on the UPN network. As a result of the Hulk, and later She-Hulk, being unavailable to the crew, the Lizard was written in the Hulk's place in the three "Secret Wars" episodes to make the story more "Spider-Man centric" than the "Secret Wars" comic mini-series. It remains unclear if the crew of "Spider-Man" were able to use the Hulk, yet simply never got around to using him, in the show's first three seasons before the Hulk got his own animated series.