Joseph Hill "Joss" Whedon, born on June 23, 1964, is an American filmmaker, comic book writer, and composer who has left an indelible mark on the landscape of modern genre television and cinema. He is best known as the visionary creator of several iconic television series, including the supernatural drama Buffy the Vampire Slayer and its spinoff Angel, the short-lived but deeply beloved space Western Firefly, the Internet musical miniseries Dr. Horrible's Sing-Along Blog, the science fiction drama Dollhouse, and the later science fiction drama The Nevers. His influence extends to the blockbuster realm as the writer and director of the Marvel Cinematic Universe films The Avengers and Avengers: Age of Ultron, as well as a co-writer on the DC Extended Universe's Justice League.

Whedon’s career began in the world of sitcoms, where he honed his sharp, witty dialogue before making his feature film writing debut with the poorly received horror comedy Buffy the Vampire Slayer in 1992. He would later brilliantly adapt this concept into the critically acclaimed television series of the same name, which premiered in 1997 and became a cultural phenomenon, cementing his reputation as a master of blending supernatural horror with complex character drama and feminist themes. His other early film work included co-writing the screenplay for the Pixar animated classic Toy Story and writing the science fiction horror film Alien Resurrection. After finding immense success as a television showrunner, Whedon returned to film to write and direct the feature-length continuation of his series Firefly with Serenity, co-write and produce the horror comedy The Cabin in the Woods, and direct a black-and-white adaptation of Shakespeare’s Much Ado About Nothing. He achieved his greatest commercial success with his work in the Marvel Cinematic Universe, writing and directing the ensemble superhero film The Avengers and its sequel, Avengers: Age of Ultron, and also co-creating the series Agents of S.H.I.E.L.D.. In 2017, he was brought in to handle reshoots for Justice League, replacing Zack Snyder, who retained final directorial credit.

Beyond his work in film and television, Whedon is a prolific composer, most notably for the musical episode of Buffy the Vampire Slayer titled "Once More, with Feeling" and for Dr. Horrible's Sing-Along Blog. He has also had a significant career as a comic book writer, penning continuations of his own television series and working on established franchises such as Astonishing X-Men. Beginning in July 2020, Whedon became the subject of numerous allegations from actors, producers, and writers who spoke out about toxic workplace environments they claim he created on many of his projects. While Whedon has denied any wrongdoing, he has acknowledged that he can be "confrontational," a controversy that has cast a shadow over his legacy and altered the public perception of the celebrated creator.