Nero was a Romulan miner originating from the late 24th century, and captain of the mining vessel Narada. Following the destruction of Romulus in 2387 caused by a star going supernova, he sought vengeance against those he felt were responsible, ultimately resulting in him being sucked in by a black hole and transported back in time to the year 2233. Nero's actions in the past resulted in the creation of an alternate reality. In this reality, his actions led to the destruction of the USS Kelvin as well as the deaths of its two senior officers, Captain Richard Robau and Lieutenant Commander George Kirk. George Kirk's death altered the upbringing of his son James T. Kirk who, in this timeline, did not join Starfleet until 2255.
In 2258, Nero was responsible for the destruction of the alternate reality's Vulcan, which resulted in the deaths of the majority of the Vulcan race. He also attempted to destroy this timeline's Earth, but his plot was foiled by Kirk and the crew of the USS Enterprise. Nero apparently died when Spock caused the Jellyfish, a small ship carrying red matter, to collide with the Narada, creating a black hole in the center of the Romulan ship. Kirk gave Nero and his crew the chance to be saved, but Nero viciously refused the offer. Kirk then ordered his crew to fire upon the ship as it was being sucked into the black hole. As Nero watched his ship being sucked into the black hole while being blasted by the Enterprise, he accepted his fate and closed his eyes as his ship was sucked in, killing him and his crew.
Russell Crowe was considered for the role of Nero before Bana was cast. In fact Crowe and Bana were director JJ Abrams' only two choices for the role.
Screenwriters Alex Kurtzman and Roberto Orci named Nero after the Roman emperor of the same name, as a nod to the Roman inspirations of the Romulans.
In the script of Star Trek, Nero seemed significantly more compassionate to Humans than he is in the final version of the film, at one point commenting, "It's not the fault of the human race that Starfleet chose Earth as its center. You're a more noble race than my fallen cousins. I'll take no pleasure in your extinction." The script also had Nero kill Ayel prior to the Battle of Earth, and Nero's scripted last words were "Forgive me… Romulus…"
Eric Bana improvised Nero's speech patterns.
In a deleted scene, Nero is interrogated by a Klingon on the prison planet Rura Penthe, and escapes. This sequence also contains Nero's line, "the wait is over", as seen in trailers for the film.
When writer Cameron Crowe saw a rough cut of the film, he kept asking who played the villain. He was staggered to realize that this was Eric Bana.