The film was released to mixed reviews, with critics praising the action sequences and Green's performance but criticizing the story and overstylized gore. It grossed over $337 million worldwide from a $110 million budget.
Queen Gorgo of Sparta tells her men about the Battle of Marathon, in which King Darius of Persia was killed by General Themistocles of Athens ten years earlier. Darius's son, Xerxes, witnesses his father's death, and is advised to not continue the war, since only "the gods can defeat the Greeks". Darius's naval commander, Artemisia, claims that Darius' last words were in fact a challenge and sends Xerxes on a journey through the desert. Xerxes finally reaches a cave and bathes in an otherworldly liquid, emerging as the 8-feet tall "god-King". He returns to Persia and declares war on Greece to avenge his father.
As Xerxes's forces advance towards Thermopylae, Themistocles meets with the council and convinces them to provide him with a fleet to engage the Persians at the sea. Themistocles then travels to Sparta to ask King Leonidas for help, but is informed by Dilios that Leonidas is consulting the Oracle, and Gorgo is reluctant to side with Athens. Themistocles later reunites with his old friend Scyllas, who infiltrated the Persian troops and learned Artemisia was born Greek, but defected to Persia as her family was raped and murdered by Greek hoplites and she was taken as a sex slave, and subsequently left for dead in the streets. She was rescued and adopted by a Persian emissary. Her lust for vengeance gained the attention of King Darius and he made her a naval commander after she killed many of his enemies. Themistocles also learns that Leonidas has marched to fight the Persians with only 300 men.
Themistocles leads his fleet of fifty warships and several thousand men, which include Scyllas, Scyllas's son Calisto and Themistocles' right-hand man Aeskylos to the Aegean Sea, starting the Battle of Artemisium. They ram their ships into the Persian ships, charge them, slaughtering several soldiers before retreating from the sinking Persian ships. The following day, the Greeks feign a retreat and lead a group of Persian ships into a crevice, where they become stuck. The Greeks charge the Persian ships from the cliffs above and kill more Persians. Impressed with Themistocles' skills, Artemisia brings him onto her ship where she seduces him, in an attempt to lure him to the Persian side as her second-in-command. He refuses, causing her to push him aside and swear revenge on him.
The Persians spill tar into the sea and send suicide bombers to swim to and board the Greek ships with their flame bombs. Artemisia and her men fire flaming arrows and torches to ignite the tar, but an Athenian manages to kill one of the Persians, who falls into the tar carrying a torch, causing ships from both sides to explode. Themistocles is thrown into the sea by an explosion and nearly drowns before being rescued by Aeskylos, and stands by Scyllas's side as he succumbs to his injuries. Believing Themistocles to be dead, Artemisia and her forces withdraw. After recovering from his injuries, Themistocles learns that only a few hundred of his warriors and six of his ships survived the disastrous attack executed by Artemisia.
Daxos, an Arcadian general, tells Themistocles that Leonidas and his 300 men have been killed after Ephialtes betrays the Greeks to Xerxes. Themistocles returns to Athens and confronts Ephialtes. The deformed Spartan traitor reveals that Xerxes plans to attack and burn Athens to the ground. Ephialites is regretful of his actions, and is welcoming death. Themistocles spares him instead, so he can warn Xerxes that the Greek forces are gathering at Salamis. He then visits Gorgo in Sparta while she is mourning Leonidas's death to ask for her help, but she is too overcome with grief. Before leaving, Themistocles returns Leonidas's sword, which had been delivered to him by Ephialtes under Xerxes's orders, and urges Gorgo to avenge Leonidas.
In Athens, Xerxes's army is laying waste when Ephialtes arrives to deliver Themistocles' message. Upon learning he is alive, Artemisia leaves to ready her entire navy for battle. Xerxes suggests a more cautious plan but she still leaves for battle, ignoring Xerxes's advice. The remaining Greek ships charge into the Persians ships, and the two armies battle, beginning the decisive Battle of Salamis. Themistocles and Artemisia fight, which ends in a stalemate with both receiving severe injuries.
At this moment Gorgo, who had been narrating the tale to the Spartans, arrives at the battle along with ships from numerous Greek city states including Delphi, Thebes, Olympia, Arcadia, and Sparta, all of them uniting against the surrounded Persians. Daxos leads the Arcadian army while Themistocles urges Artemisia to surrender. Xerxes, watching the battle from a cliff, turns his back on her, acknowledging his naval defeat and continues the march of his army. Artemisia tries to kill Themistocles one last time but is killed as he stabs her through the stomach. While Dilios leads the Greek assault, Themistocles and Gorgo take a moment to silently acknowledge one another's alliance as the remaining Persians attempt a counter-attack. The three then charge at the opposing Persians with the whole Greek army.
In June 2008, producers Gianni Nunnari, Mark Canton, and Bernie Goldmann revealed that work had begun on a sequel to 300. Legendary Pictures announced that Frank Miller, who wrote the 1998 comic book limited series on which the film 300 was based, was writing a follow-up graphic novel, and Zack Snyder, co-screenwriter and director of 300, was interested in directing the adaptation, but instead chose to develop and direct the Superman reboot Man of Steel. Noam Murro directed instead, while Snyder produced. The film was centered on the Greek leader Themistocles, portrayed by Australian actor Sullivan Stapleton. During pre-production, the film was titled 300: Battle of Artemisium (although this was widely misreported as "Battle of Artemisia"); the film was retitled 300: Rise of an Empire in September 2012.
Principal photography commenced in early July 2012 at the Nu Boyana Film Studios in Sofia, Bulgaria. On May 10, 2013, it was announced the film's release date would be pushed back from August 2, 2013, to March 7, 2014.
300: Rise of an Empire grossed $106.6 million in North America and $231 million in other territories for a worldwide total of $337.6 million, against a production budget of $110 million.
In North America, the film opened to number one in its first weekend with $45 million. In its second weekend, the film dropped to number two, grossing an additional $19.2 million. In its third weekend, the film dropped to number five, grossing $8.5 million. In its fourth weekend, the film dropped to number nine, grossing $4.2 million.
300: Rise of an Empire received mixed reviews from critics. Review aggregation website Rotten Tomatoes gives the film an approval rating of 43% based on 172 reviews, with an average rating of 4.9/10. The site's critical consensus reads, "It's bound to hit some viewers as an empty exercise in stylish gore, and despite a gonzo starring performance from Eva Green, 300: Rise of an Empire is a step down from its predecessor." On Metacritic, the film has a score of 48 out of 100 score, based on 34 critics, indicating "mixed or average reviews". Audiences polled by CinemaScore gave the film an average grade of "B" on an A+ to F scale.
Todd Gilchrist of The Wrap gave the film a negative review, saying "Rise of an Empire lacks director Snyder's shrewd deconstruction of cartoonish hagiography, undermining the glorious, robust escapism of testosterone-fueled historical reenactment with an underdog story that's almost too reflective to be rousing." Todd McCarthy of The Hollywood Reporter gave the film a negative review, saying "Although Gerard Butler's star has significantly fallen due to the 17 mediocre films he's made since 300, it must be admitted that he's missed here." Scott Foundas of Variety gave the film a positive review, saying "This highly entertaining time-filler lacks the mythic resonances that made 300 feel like an instant classic, but works surprisingly well on its own terms." Guy Lodge of Time Out gave the film three out of five stars, saying "It's flesh and carnage that the audience is here to see, and Murro delivers it by the glistening ton, pausing only for stray bits of backstory." Kyle Smith of the New York Post gave the film two and a half stars out of four, saying "The film works as a high-tech boy-fantasy successor to Conan the Barbarian." Soren Anderson of The Seattle Times gave the film three out of five stars, saying "Rise of an Empire is not great by any stretch of the imagination, but it's very impressive in its single-minded dedication to creating a moviegoing experience designed to totally engulf its audience." James Rocchi of Film.com gave the film a zero out of ten, saying "Long on crimson spurts of blood but low on character, larded with production value but bereft of any other kind of it, 300: Rise of an Empire is a 3D joke."
James Berardinelli of ReelViews gave the film two and a half stars out of four, saying "The lack of a creative driver behind the film leads to a level of fundamental dissatisfaction. The movie delivers all the necessary elements but their impact is dull." Joe Neumaier of the New York Daily News gave the film one out of five stars, saying "The film winds up looking like an ashen video game. It's even more muddy in IMAX and 3-D." Colin Covert of the Star Tribune gave the film two out of four stars, saying "300: Rise of an Empire plays like a collaboration between the Marquis de Sade and Michael Bay. Or maybe the History Channel and the Saw franchise." Ann Hornaday of The Washington Post gave the film one out of four stars, saying "Rise of an Empire is no fun at all - even those famous six-pack abs from 300 seem to be missing a can or two in this desperate attempt to up an already dubious ante." Drew Hunt of the Chicago Reader gave the film a negative review, saying "The slow-motion battle scenes are technically impressive and occasionally elegant, but there's enough machismo here to choke a thousand NFL locker rooms." Richard Roeper gave the film three and a half stars out of four, calling the film "A triumph of production design, costumes, brilliantly choreographed battle sequences and stunning CGI."
Scott Bowles of USA Today gave the film two out of four stars, saying "For anyone looking for a sense of script (forget plausibility), Empire is a Trojan horse." Betsy Sharkey of the Los Angeles Times gave the film a positive review, saying "The spectacularly brutal fighting is the film's main calling card, and in that Rise of an Empire doesn't disappoint." Nicolas Rapold of The New York Times gave the film a mixed review, saying "The naval collisions and melees play out in panel-like renderings that are bold and satisfying for the first half-hour but lack the momentum and bombastic je ne sais quoi of 300." David Hiltbrand of The Philadelphia Inquirer gave the film two and a half stars out of four, saying "With its slo-mo ultraviolence, gushers of blood, impressive 3-D effects, homoerotic subtext, and self-important plot, this is a fan boy's fantasy, a four-star wonderment." Tom Long of The Detroit News gave the film a D, saying "300: Rise of an Empire is a bloodbath and not much else." Adam Nayman of The Globe and Mail gave the film one and a half stars out of four, saying "An extension of the 300 universe, like an add-on content pack for a video game." Mark Jenkins of NPR gave the film a negative review, saying "If the movie's action recalls video games, the dramatically artificial lighting suggests 1980s rock videos. Indeed, Rise of an Empire is so campy that it might work better as a musical." Stephen Whitty of the Newark Star-Ledger gave the film one and a half stars out of four, saying "There is much grinding of teeth, and mauling of history, and anachronistic use of gunpowder, until we plug our ears and desperately pray to the gods of Olympus, or the brothers of Warner, that they might make an end."
Despite mixed reviews for the film as a whole, Eva Green's performance as the naval officer Artemisia received rave reviews, with some going so far as to say she was more interesting than the heroes, and saved the film. Ty Burr of The Boston Globe, in his positive review stated, "Rise of an Empire may strike some as an improvement on the first film, if only for two reasons: naval warfare and the glorious absurdity of Eva Green." According to Rafer Guzman's Newsday review, "The one bright spot is Eva Green as Xerxes' machinator, Artemesia, a raccoon-eyed warrior princess... Green plays a snarling, insatiable, self-hating femme fatale and completely steals the show." And perhaps most emphatically, Stephanie Zacharek writing for The Village Voice exclaimed, "Rise of an Empire might have been essentially more of the same, but for one distinction that makes it 300 times better than its predecessor: Mere mortals of Athens, Sparta, and every city from Mumbai to Minneapolis, behold the magnificent Eva Green, and tremble!"
Paul Cartledge, a professor of Greek culture at Cambridge University, noted that the film contains historical errors. For example, Darius was not killed as depicted as neither Xerxes nor Darius was present at the Battle of Marathon. Artemisia, historically a queen and not an abused, orphaned slave, actually argued against sailing into the straits and survived the Persian Wars. The Spartan navy contributed a mere sixteen warships to the Greek fleet of 400 warships in the ending battle scene, not the huge armada shown.
300: Rise of an Empire was released on the iTunes Store on June 3, 2014, and was released on DVD and Blu-ray on June 24.
Snyder told Collider that more sequels could go beyond Ancient Greece to the Revolutionary War and a battle in China.