If you travelled back in time to 1990, visited the Roseanne set at ABC Studios, and told 25-year old Joss Whedon that he’d someday helm the most successful film franchise in history, he probably wouldn’t believe you. Oh, he’d probably believe you came from the future in an incomprehensible time machine, but he probably wouldn’t believe the success that he’d bring to an Avengers film franchise and the Marvel Cinematic Universe in general. And who could blame him? Whedon’s humble, cult beginnings have grown into an unbelievable career filled with vampires, space cowboys, toy cowboys, Shakespearean prose, and – most recently – a Hulk. In honor of Avengers: Age of Ultron opening this week, we’re taking a look at the works of Joss Whedon in the latest installment of Eventful’s Director Series.

In retrospect, the promise of Whedon’s success was engrained in his DNA. His grandfather, John, was a writer on The Donna Reed Show, and his father, Tom, wrote for The Electric Company and Golden Girls. After graduating from Wesleyan University, he found his first writing jobs working on Roseanne and Parenthood. In 1992, Whedon’s original script for Buffy the Vampire Slayer was optioned turned into a teen comedy. While it was a considerably successful first film, Whedon stated the released version diverged greatly from his vision. From there, Whedon became a script doctor: making minor improvements to scripts for films like Speed and Waterworld while often receiving no credit.

Whedon’s first big success as a writer was working on Toy Story, for which he and the other Pixar writers received an Oscar nomination. While Whedon continued to write for film (Alien: Resurrection, Atlantis: The Lost Empire), the attention from his Oscar nod came with the opportunity to create Buffy as he had envisioned; albeit, on a smaller screen. Running with the concept “high school as a horror movie”, Buffy the Vampire Slayer ran for seven seasons, launched the careers of Sarah Michelle Gellar and Alyson Hannigan, and produced the popular spinoff Angel; both shows remaining cult favorites to this day.

Before Buffy ended, Whedon was already hard at work on his next television project. Based on the writer’s empathy for the Confederate soldiers at Gettysburg, Firefly followed an irascible space captain who fought on the losing side of a war, and his adventures taking on a (semi) normal life as a smuggler afterwards. Despite their shiny adventures, Captain Mal and the crew of the Firefly experienced a sudden but inevitable betrayal when the show was cancelled after its first season. However, fans decried the cancellation and campaigned for more. They got their wish three years later when Whedon filmed Serenity. The feature length film not only gave the fans one last dose of action, but also wrapped up Whedon’s general vision for the story (sorry Wash).

Whedon’s next project was a labor of love, a chance to collaborate with family, and a product of the Writers Guild of America Strike in 2007. After finding how well he worked with his half-brothers Zack, Jed, and Jed’s wife Maurissa Tancharoen, they all decided to create a musical. After failing to find any financial backing to support them during the strike, they decided to produce it themselves and release it online. This allowed Whedon to create free of studio demands, release something that people could easily afford, and avoid all of the sensitive issues that caused the Writers’ Guild to strike. The result was Dr. Horrible’s Sing-Along Blog: a musical that combined elements of classic Greek tragedy, touching romance, and kitschy superheroism. The miniseries was acclaimed by critics and viewers alike and won numerous short-form awards; including a Creative Arts Emmy Award.

Not content to turn the horror genre on its ear just once, Whedon played with a groundbreaking twist on the “teen slasher” genre in Cabin in the Woods. While the film presented an interesting new take on how promiscuous teens find themselves in such deadly situations, it was also a loving lampoon of the genre. It parodied the ridiculousness of some flimsy plot lines that get rehashed, as well as the “torture porn” that became popular after Saw.

It’s no big surprise to comic book fans that Whedon was chosen as the director who would unite Marvel Studios’ new superheroes in Marvel’s The Avengers. He wrote two iconic storylines for the X-Men in the 2000’s, one of which became the basis for X-Men: The Last Stand. He also contributed to the storyline of the Civil War event, which is the subject of the upcoming Captain America: Civil War movie (which Whedon, ironically, has no hand in). Whedon also contributed to the scripts of Captain America: The First Avenger and Thor, and his familiarity with the team made him the obvious choice. While a superhero blockbuster was nothing new, and audiences were already familiar with the characters, Whedon gave each character a different element of humanity and a sense of duty that allowed the heroes with different backgrounds and values to come together for a common good. Visually stunning action, deft character development, and an epic storyline made Marvel’s The Avengers Whedon’s biggest success yet.

That being said, critics are already claiming that Whedon outdid himself with Avengers: Age of Ultron. Honing his skills while creating the Agents of S.H.I.E.L.D. TV show has given Whedon new insight into the Marvel Universe. Explosive action only accounts for part of Marvel Studio’s popularity, and Whedon knew he had to take the characters to darker places to make their victory more thrilling. On the surface, all of his projects seem like pure, fun action, but it’s the depth and relatability of the characters that makes the fight so gripping. He speaks to the hero in all of us, and then takes us on a journey to the stars.