Portman was born in West Jerusalem and raised in Long Island, New York, where she began her acting career at twelve, starring as the young protégée of a hitman in Léon: The Professional (1994).

While still in high school, she made her Broadway debut in The Diary of a Young Girl (1998) and gained international recognition for her role as Padmé Amidala in Star Wars: Episode I – The Phantom Menace (1999).

During this time, she took fewer acting roles but continued to appear in the Star Wars prequel trilogy (2002 and 2005) and performed in a 2001 revival of Anton Chekhov's The Seagull at The Public Theater.

Her parents were reluctant to let her do the part due to the explicit sexual and violent nature of the script, but agreed after Besson took out the Mathilda character's nudity and killings that she committed.

[26] Hal Hinson of The Washington Post commended Portman for bringing a "genuine sense of tragedy" to her part, but Peter Rainer of the Los Angeles Times believed that she wasn't "enough of an actress to unfold Mathilda's pain" and criticized Besson's sexualization of her character.

[39] Michael Mann offered her the small part of the suicidal stepdaughter of Al Pacino's character in the action film Heat (1995) for her ability to portray dysfunction without hysteria.

[40][41] Impressed by her performance in The Professional, the director Ted Demme cast her as a precocious teenager who flirts with her much-older neighbor (played by Timothy Hutton) in the ensemble comedy-drama Beautiful Girls (1996).

[44] Portman was cast opposite Leonardo DiCaprio in Baz Luhrmann's Romeo + Juliet (1996), but she dropped out during rehearsals when studio executives found her too young for the role.

[26][34] She later bemoaned that her parts in The Professional and Beautiful Girls prompted a series of offers to play a sexualized youngster, adding that it "dictated a lot of my choices afterwards 'cos it scared me ... it made me reluctant to do sexy stuff".

[58][59][60] Her high school paper, "A Simple Method to Demonstrate the Enzymatic Production of Hydrogen from Sugar", co-authored with scientists Ian Hurley and Jonathan Woodward, was entered in the Intel Science Talent Search.

[65] After finishing work on the film, she began attending Harvard University to pursue her bachelor's degree in psychology, and significantly reduced her acting roles over the next few years.

[27][67] In the summer of 2001, she returned to Broadway (at the Delacorte Theater) to perform Chekhov's drama The Seagull, which was directed by Mike Nichols and co-starred Meryl Streep and Philip Seymour Hoffman.

[68] Linda Winer of Newsday wrote that the "major surprises come from Portman, whose Nina transforms with astonishing lyricism from the girl with ambition to Chekhov's most difficult symbol of destruction".

[89] Portman's final film role in 2005 was that of Evey Hammond in the political thriller V for Vendetta, based on the comics of the same name, about an alternative future where a neo-fascist regime has subjugated the United Kingdom.

[90] Ruthe Stein of the San Francisco Chronicle deemed it Portman's strongest performance to that point, and remarked that she "keeps you focused on her words and actions instead of her bald head.

[100] Richard Corliss of Time magazine believed that "for once she's not playing a waif or a child princess but a mature, full-bodied woman" and commended her "vibrancy, grittiness and ache, all performed with a virtuosa's easy assurance".

[106] Derek Elley of Variety was critical of Portman's English accent and wrote that she "doesn't quite bring the necessary heft to make Anne a truly dominant power player".

She liked the idea of Kenneth Branagh directing a big-budget film that emphasized character; she signed on to it before receiving a script, and helped develop her part by reading the biography of scientists such as Rosalind Franklin.

[142] In 2015, Portman appeared alongside an ensemble cast, including Christian Bale, in Terrence Malick's experimental drama film Knight of Cups, which marked her first project after giving birth.

[143] Based on Israeli author Amos Oz's autobiographical novel of the same name which is set in Jerusalem during the last years of the British Mandate of Palestine, the Hebrew-language film starred Portman who also produced and co-wrote it.

She was initially intimidated to take on the part of a well-known public figure,[153] and eventually researched Kennedy extensively by watching videos of her, reading books, and listening to audiotapes of her interviews.

[156] David Rooney of The Hollywood Reporter termed it an "incandescent performance" and added that "her Jackie is both inscrutable and naked, broken but unquestionably resilient, a mess and yet fiercely dignified".

[158][159] She also served as producer for the comedy horror film Pride and Prejudice and Zombies, directed by Burr Steers, and starred in Rebecca Zlotowski's French-Belgian drama Planetarium.

[167] Her next appearance was in Xavier Dolan's first English-language film, the ensemble drama The Death & Life of John F. Donovan (2018), which was termed a "shocking misfire" by Eric Kohn of IndieWire.

[170] Comparing it to her performances in Black Swan and Jackie, Robbie Collin of The Daily Telegraph wrote that "this role has a similar audacity and extravagance that few actresses would dare attempt, let alone be allowed to get away with".

[198][199] Portman has long been an advocate for various causes, including animal rights, where she became a vegetarian at age eight after witnessing a demonstration of laser surgery on a chicken during a medical conference with her father.

In 2004 and 2005, she traveled to Uganda, Guatemala, and Ecuador as the Ambassador of Hope for FINCA International, an organization that promotes micro-lending to help finance women-owned businesses in developing countries.

[227] In February 2015, Portman was among other alumni of Harvard University including Robert F. Kennedy Jr., Darren Aronofsky and Susan Faludi who wrote an open letter to the school demanding it divest its $35,900,000,000 endowment from coal, gas, and oil companies.

"[231] She drew attention to the MeToo movement, revealing that her first fan letter was a "rape fantasy" from a man and that her local radio station created a countdown until her eighteenth birthday (when she would reach legal age to consent to have intercourse).

She explained that she did not want to "appear as endorsing" Prime Minister Netanyahu, who was scheduled to speak at the ceremony, and emphasized that "the mistreatment of those suffering from today’s atrocities is not in line with my Jewish values."