She first gained public attention in 2015 with her debut single "Ocean Eyes", written and produced by her brother Finneas O'Connell, with whom she collaborates on music and live shows.

Its single "Bad Guy" became the first by an artist born in the 21st century to top the US Billboard Hot 100 and be certified Diamond by the Recording Industry Association of America (RIAA).

Her third album, Hit Me Hard and Soft (2024), was met with critical acclaim and spawned the US top-five singles "Lunch" and "Birds of a Feather", with the latter becoming her first number-one on the Billboard Global 200.

[7] Eilish has a history of political activism, focusing on climate change awareness, women's reproductive rights, and gender equality.

[18][19] Eilish and her older brother Finneas were homeschooled by Baird, a decision their parents made to spend time with them and give them the freedom to pursue their interests.

[24][21] Eilish took some acting auditions, which she disliked, but she enjoyed recording background dialogue for crowd scenes and worked on the films Diary of a Wimpy Kid, Ramona and Beezus, and the X-Men series.

[26][22][29][30] The song received several hundred thousand listens in two weeks, and Finneas's manager, Danny Rukasin, reached out to him to discuss Eilish's potential.

[35] In January 2016, Finneas and his manager arranged a deal in which Apple Music signed Eilish to A&R company Platoon, specializing in packaging emerging artists before they get a major-label contract.

[12] On March 24, 2016, a music video for "Ocean Eyes" directed by Megan Thompson premiered on Eilish's official YouTube channel.

[72] For Record Store Day 2018, Eilish released "Party Favor" on a pink 7-inch vinyl, along with a cover of "Hotline Bling", by Drake, as the B-side.

[73] Eilish collaborated with American singer Khalid on the single "Lovely", which was released on April 19, 2018, and added to the soundtrack for the second season of 13 Reasons Why.

[76] On the day of release for her single "When the Party's Over",[77] Eilish was featured in Vanity Fair's "73 Questions" rapid-fire questionnaire video series by Joe Sabia, who revisited an interview from October 2017.

[106] On January 14, 2020, Eilish was announced as performer of the title track for the 25th installment in the James Bond film franchise, No Time to Die,[107] written and produced with her brother.

The Livestream set to air from Los Angeles on October 24, with proceeds from the show's merchandise raising funds to support event crew members affected by the COVID-19 pandemic.

[121] "Lo Vas a Olvidar", a single featuring Rosalía as a part of HBO's Euphoria soundtrack, was released in January 2021, almost two years after initially teasing the song.

In her acceptance speech for Record of the Year, Eilish said that Megan Thee Stallion "deserved to win", but still thanked her fans and her brother for her award.

[124] In 2021 she published her personally selected comprehensive book of photographs that shared "an intimate window into her life" on and off stage, By - Billie Eilish.

The collector's item was available only at a number of Gucci stores around the world and included Gucci-branded nail stickers designed by the brand's creative director, Alessandro Michele.

[134] In June 2021, Eilish was criticized online for videos in which she mouthed the anti-Asian slur "chink" while lip-syncing the song "Fish" by Tyler, the Creator,[135][136] while Matthew Tyler Vorce, her reported boyfriend at the time, received criticism for alleged social media posts in which he used offensive language and slurs against gay and Black people.

[140][141][142] On June 22, she posted an apology to Instagram stories for her usage of "chink", saying that she was "appalled and embarrassed" by the video and that she was "13 or 14" at the time and did not know the slur was a derogatory term.

[154][155] Eilish worked with Apple Music to exclusively host a film of one of the Happier Than Ever tour concerts, specifically one of her shows at The O2 Arena in London.

[173] On August 11, 2024, Eilish performed "Birds of a Feather" on Belmont Shore, Long Beach, during the 2024 Summer Olympics closing ceremony as part of the handover to Los Angeles, which would host the Games in 2028.

[200] Eilish grew up listening to the Beatles, Justin Bieber, Green Day,[201] the 1975,[202] Arctic Monkeys, Linkin Park[203] and Lana Del Rey.

[208][209] Other influences include Adele,[210] Earl Sweatshirt, James Blake, Amy Winehouse, the Spice Girls, Lorde, Marina and the Diamonds, Britney Spears, Taylor Swift, Nicki Minaj, XXXTentacion, and Twenty One Pilots.

"[244] In May 2019, Eilish appeared in a Calvin Klein advertisement, where she mentioned that she dresses in baggy clothes to prevent people from judging her body.

[251] Though the dress was inspired by the original Barbie doll, fashion critics observed its likeness to Golden Age star Marilyn Monroe, who wore a tulle de la Renta gown in the early 1950s.

[255] Eilish also collaborated with Adobe Creative Cloud the same month for a series of advertisements[256] as well as a social media art contest, where users would submit artwork with the hashtag "#BILLIExADOBE".

[279][280][281] Among other pursuits, Eilish signed an open letter to world leaders urging them to take action against climate-induced poverty,[282] embarked on an ad campaign encouraging young people to use technology for environmental advocacy, and hosted a six-day climate seminar in London titled Overheated to discuss topics such as sustainable fashion and youth activism.

[283][284] Her 2019 single "All the Good Girls Go to Hell" and its subsequent video center around climate change and use heaven-and-hell imagery to criticize ignorance of rising sea levels,[285][286] and she permitted the nonprofit CoralWatch to use "Ocean Eyes" as part of an online awareness campaign about Australia's Great Barrier Reef.

[287] She is a regular advocate on social media for animal rights and veganism, and has criticized the dairy,[288] mink fur,[289] and wool [290] industries.