It was released on 15 November 2002 in the United Kingdom and North America. The film was very well received at the box office, making US$879 million worldwide and is the 34th highest-grossing film of all time and the seventh highest-grossing film in the Harry Potter series. It was nominated for three BAFTA Film Awards in 2003.

Severus Snape is a fictional character in J. K. Rowling's Harry Potter series. He is characterized as a person of considerable complexity, whose coldly sarcastic and controlled exterior conceals deep emotions and anguish. In the first novel of the series, Snape is a teacher who is hostile from the start toward Harry and is built up to be the primary antagonist until the final chapters. As the series progresses, Snape's character becomes more layered and complex. Rowling does not fully reveal the details of his true loyalties until the end of the final book, Harry Potter and the Deathly Hallows. Over the course of the series, Snape's portrayal evolves from that of a malicious and partisan teacher to that of a pivotal character of considerable complexity and moral ambiguity.

In the series, Snape is an exceptionally skillful wizard who primarily teaches Potions at Hogwarts school. In the sixth novel, he teaches Defence Against the Dark Arts, a position which he was known to have desired throughout the series. For much of the series, Snape's actions seem to serve Harry's nemesis, Lord Voldemort, although Harry's mentor, Dumbledore, often advises Harry that – despite his actions and animosity – Snape is trustworthy and his true loyalties can be relied upon. He ultimately becomes Headmaster of Hogwarts in the final novel, after killing Dumbledore at the end of the sixth book. Snape himself dies at the hands of Voldemort in the final chapters of the seventh book, revealing his memories and true back story to Harry (and therefore to the reader) in his last minutes. In the book's epilogue, Harry describes Snape as "one of the bravest men I knew".

In an interview, Rowling described Snape's character as an "antihero". She has said that she drew inspiration for Snape's character from a disliked teacher from her own childhood, and described Snape as a horrible teacher, saying the "worst, shabbiest thing you can do as a teacher is to bully students." However, she does suggest in the books that he is generally an effective teacher. Although Rowling has said that Gilderoy Lockhart is her only character that she "deliberately based on a real person", Snape was reportedly based, at least in part, on John Nettleship, who taught Rowling chemistry and employed her mother as an assistant at Wyedean School near Chepstow. For Snape's surname, Rowling borrowed the name of the village of Snape, Suffolk. In a 1999 interview and again in 2004, Rowling singled out Snape as one of her favourite characters to write.

Rowling was less forthcoming about Snape than she was for other characters, because his true loyalties and motivations were not revealed until the final book. However, she hinted numerous times at Snape's important role, suggesting that people should "keep their eye on Snape". In 1999, answering a question regarding Snape's love life and the redemptive pattern to his character, Rowling expressed her surprise at the foresight. Rowling also disclosed that after the publication of Prisoner of Azkaban, there was one female fan who guessed Snape loved Lily Potter, making Rowling wonder how she had given herself away.

After the completion of the series, Rowling began to speak openly about Snape, discussing the contrast between his character arc and that of Albus Dumbledore. Rowling said "the series is built around [the Dumbledore and Snape storylines]", and maintained that she always knew what Snape would turn out to be at the end and that she carefully plotted his storyline throughout the series. "I had to drop clues all the way through because as you know in the seventh book when you have the revelation scene where everything shifts and you realise...what Snape's motivation was. I had to plot that through the books because at the point where you see what was really going on, it would have been an absolute cheat on the reader at that point just to show a bunch of stuff you've never seen before." Rowling further said in an interview that she wanted Snape to find redemption and forgiveness: "Snape is a complicated man...he was a flawed human being, like all of us. Harry forgives him...Harry really sees the good in Snape ultimately... I wanted there to be redemption."

Severus Snape appears in all eight Harry Potter films, portrayed by British actor Alan Rickman. Rickman was Rowling's personal choice to portray the character. He had conversations with Rowling about his character and is one of the few Harry Potter actors that she spoke to prior to the completion of the book series about the future direction of the character. "He knew very early on that he'd been in love with Lily," said Rowling. "He needed to understand […] where this bitterness towards this boy who's the living example of her preference for another man came from."

Rickman used this knowledge of Snape's ultimate loyalties throughout the films by deciding how to play certain scenes, deliver specific lines, or using body language to convey specific emotions. When the directors of the films would ask him why he was doing a scene a certain way or delivering a line in a specific manner, Rickman would simply reply that he knew something they didn't.

Rickman himself refrained from talking about Snape, asking readers to wait and "see what unfolds" in the course of the novels; however, he did say Snape is a complicated person, very rigid and full of himself; in an interview he went further, saying: "Snape isn't one who enjoys jokes and I strongly fear that his sense of humour is extremely limited... But in his defence, I will add that he didn't have an easy adolescence, particularly during his studies at Hogwarts." He also said Snape is a fascinating character, and that he takes immense pleasure in playing such an ambiguous person.

Rickman's performance as Snape was widely acclaimed by critics, fans and Rowling herself. Entertainment Weekly listed Rickman as one of the most popular movie stars in 2007 for his performance as Snape, saying: "As the icy, humourless magic instructor Severus Snape, Rickman may not be on screen long—but he owns every minute." Rickman also noted fans' reactions; in an interview, he said he found "that people in general adore Snape. He is sarcastic, stubborn, etc, etc. But he is also fascinating. I have a lot of fun impersonating him." Rickman was nominated for several awards for his portrayal of Snape, and in 2011, was elected the best character portrayal in all the Harry Potter films series.

In 2011, Empire magazine published an open letter from Rickman to J.K. Rowling, ruminating on the ten years of working on the Potter films and thanking her for telling the story.

Alan Sidney Patrick Rickman (born 21 February 1946) is an English actor. Rickman is a former member of the Royal Shakespeare Company in both modern and classical theatre productions. His breakout performance was as the Vicomte de Valmont in Les Liaisons Dangereuses, for which he was nominated for a Tony Award. Rickman is well known for his film performances as Hans Gruber in Die Hard, Sheriff of Nottingham in Robin Hood: Prince of Thieves (for which he won the BAFTA Award for Best Actor in a Supporting Role in 1991), Severus Snape in the Harry Potter film series, Éamon de Valera in Michael Collins, Metatron in Dogma, and Ronald Reagan in The Butler.

Rickman has also had a number of other notable film roles such as Jamie in Truly, Madly, Deeply, Colonel Brandon in Ang Lee's 1995 film Sense and Sensibility, Harry in Love Actually, P.L. O'Hara in An Awfully Big Adventure. More recently, he played Judge Turpin in the film adaptation of Stephen Sondheim's musical of Sweeney Todd: The Demon Barber of Fleet Street. In 1995, he was awarded the Golden Globe, Emmy Award and Screen Actors Guild Award for his portrayal of Rasputin in Rasputin: Dark Servant of Destiny.

As of 2013, Rickman has won a BAFTA Award, a Golden Globe Award, an Emmy Award and a Screen Actors Guild Award. He has been nominated twice for a Tony Award and several times for a BAFTA Award. In 2010, he was named one of the best actors to have never received an Academy Award nomination.