Welcome back, Frank.
The Punisher series, while grounded in a gritty New York City reality, gives us plenty of nods to the Punisher comic books, like the inclusion of the Battle Van and most prominently, the introduction of Micro, a character first teased in Daredevil. Here, Frank's computer savvy accomplice is reimagined as a government secrets leaking Edward Snowden type. The series' excellent first episode, "3 a.m.," which could operate as a self-contained The Punisher movie, ends with Micro uttering the words, "Welcome Back, Frank." It's a nod to the 12-issue limited series written by Garth Ennis published in 2000 and later collected as a trade paperback called Welcome Back, Frank, which also served as partial inspiration for the 2004 Punisher movie.
The Gnucci Crime Family.
Those dummies at the work site who shouldn't have tangled with Frank Castle were full of bad ideas, including the big robbery that ultimately lead to their demise. They dared to rip-off the Gnucci crime family! Comic book fans should instantly recognize the name, as the Gnucci crime syndicate were major villains in Welcome Back, Frank.
The Dogs of Hell.
The first episode in the very binge worthy Punisher series provided some connective tissue to the greater Marvel Universe, as well. While we don't see any of the Defenders, let alone the Avengers, in The Punisher, we do get another glimpse of the Dogs of Hell, the biker gang seen in Agents of S.H.I.E.L.D. and Daredevil. The fictitious outlaw motorcycle club was subsequently introduced into the Marvel Comics universe, as one of the New York criminal crews connected to The Kingpin.
Claire Temple isn't in The Punisher but audiences were treated to another regular from Netflix's MCU stable. Turk, the fan favorite low level arms dealer played by Rob Morgan, is once again in the wrong place at the wrong time. Thankfully, in a rare act of mercy against a criminal, The Punisher spares Turk, which means he'll be alive to potentially make appearances in new seasons of Jessica Jones, Iron Fist, and the like.
A few framed newspaper items in the background give us the show's biggest reminder that The Punisher takes place in the greater Marvel Cinematic Universe. Karen Page hasn't taken down two of the articles framed by her friend and mentor, the late Ben Urich, who used to occupy her office. One is about the green goliath's battle with Abomination in The Incredible Hulk and the other is about the alien invasion of New York depicted in The Avengers, which is the event that brought Daredevil's Hell's Kitchen back to the state of disrepair depicted in the classic Daredevil comics. There's a new headline to be seen as well, presumably written by the former legal aide herself: "CHAOS UNDER THE STREETS!" This is most certainly a reference to the events of The Defenders, which culminated in an underground showdown.
The Rumble in the Jungle.
In one important scene featuring troubled Army veteran Lewis and his father, the two of them discuss the famous boxing match between Muhammad Ali and George Foreman. The so-called "Rumble in the Jungle" took place in 1974, which just so happens to be the year The Punisher debuted in The Amazing Spider-Man #129.
The Picture of Dorian Gray.
Comic books aren't the only reading material to get shout-outs in The Punisher. The series features a few nods to literary classics, the most obvious of which of course is when we see the Captain Ahab like Frank Castle reading a copy of Moby Dick. Less overt is when Frank's best friend, Billy Russo, picks up a copy of The Picture of Dorian Gray. Not only is it a hint about who his character is and where he's headed, but it's a bit of an inside joke: actor Ben Barnes starred in a 2009 movie adaptation.
Like most Marvel characters, The Punisher has appeared in all sorts of mediums, from comics to movies to video games. One of the best Easter Eggs in The Punisher series is a nod to an action figure set released by Diamond Select toys, which featured a thug laid out on a pinball machine at the hands of Frank Castle.
While the character has been reimagined to fit the mythology of the current series, Billy Russo has a deep history with the character of Frank Castle. In the comics, Russo becomes Punisher arch-nemesis Jigsaw, whose name conjures the image of his disfigured face. Of course, spoiler alert, The Punisher Season One wraps up with a clear indication that the MCU's Billy Russo is headed toward the same fate, cemented by the fact that Castle puts a bullet through his former friend's cheek before dragging his face across a broken mirror with gruesome savagery. That must've been what all of the foreshadowing about Russo being so "pretty" was all about. The Punisher Season 1 leaves Billy comatose, with bandages all over his face.
Stan Lee is still the man.
Stan "The Man" Lee returns to the Netflix corner of the MCU once again as the literal "Man," in uniform as a police officer in promotional posters for the NYPD. In The Punisher, the poster can be seen near the location of the climactic battle with Billy.