Sydney Bernice Sweeney was born on 12 September 1997 in Spokane, Washington, the elder of two children born to Lisa Sweeney, a lawyer, and Steven Sweeney, a healthcare professional. She was raised largely across the state line in the Idaho panhandle, at a lakeside family property that had belonged to her relatives for five generations, and attended Saint George’s School in Spokane, where she took part in athletics, ballet, skiing and mixed martial arts alongside her academic studies.

Sweeney’s interest in acting began after she was cast as an extra on a film shoot near Spokane as a child. At the age of eleven she reportedly presented her parents with a five-year business plan to persuade them to support a career in front of the camera, prompting the family to relocate first to Oregon for commercial auditions and then, when she was fourteen, to Los Angeles to pursue acting full time. Biography.com has detailed the unusually deliberate, business-minded approach she took to launching her career as a child.

Sweeney’s earliest screen credits were modest, beginning with a bit part on NBC’s “Heroes” in 2009 and the low-budget film “ZMD: Zombies of Mass Destruction” in 2010, followed by guest appearances on established American television series including “90210”, “Criminal Minds” and “Grey’s Anatomy” through the early 2010s. These small roles gave her steady, if unglamorous, on-set experience while she was still a teenager building her career in Los Angeles.

By 2018, Sweeney’s career had gathered real momentum, with roles across three high-profile productions in a single year: Netflix’s “Everything Sucks!”, HBO’s “Sharp Objects” alongside Amy Adams, and the second season of Hulu’s “The Handmaid’s Tale”. The Encyclopaedia Britannica credits this run of prestige-television work with establishing her as a rising talent worth watching ahead of her breakout the following year.

Sweeney’s breakthrough arrived in June 2019 with the premiere of HBO’s “Euphoria”, in which she played Cassie Howard, a role that ran across the show’s first two seasons and a Christmas special and became one of the defining performances of her career. The following year she added a second high-profile HBO role, playing Olivia Mossbacher in the first season of “The White Lotus”, Mike White’s satirical anthology series set at a Hawaiian luxury resort.

Both performances were recognised at the 2022 Primetime Emmy Awards, where Sweeney received her first two nominations in the same year, for Outstanding Supporting Actress in a Drama Series for “Euphoria” and Outstanding Supporting Actress in a Limited or Anthology Series or Movie for “The White Lotus”, an unusual double recognition that IndieWire noted made her one of the standout names of that year’s nominations morning.

Sweeney’s biggest commercial success to date came with “Anyone But You” (2023), a romantic comedy opposite Glen Powell loosely inspired by Shakespeare’s “Much Ado About Nothing”. Despite a modest opening weekend, the film became a genuine sleeper hit over the following months, eventually grossing more than $200 million worldwide against a production budget of around $25 million, a result Collider tracked as it repeatedly cleared box-office milestones through early 2024.

She followed this with “Immaculate” (2024), a horror film in which she starred and also served as executive producer, playing a young novice nun at an Italian convent. The film opened to the strongest weekend in the history of its distributor, Neon, and earned a positive 71 percent critics’ score on Rotten Tomatoes, confirming Sweeney’s ability to headline and help produce a commercially successful genre film outside the major studio system.

Sweeney’s profile continued to grow through high-visibility awards-season projects, including her physically demanding turn as boxing champion Christy Martin in “Christy” (2025), for which she gained more than 30 pounds and trained for months in a boxing gym she had built in her grandmother’s shed. The film, directed by David Michod, premiered at the Toronto International Film Festival in September 2025 ahead of a wider theatrical release that November, and was widely covered as one of the more transformative physical performances of her career. Deadline reported on the film’s TIFF premiere and reception.

Alongside her screen work, Sweeney has become a fixture of red carpets, magazine covers and major fashion campaigns, regularly named among the most searched and most photographed actresses of her generation as her filmography has broadened from television drama into studio comedy, horror and prestige biographical drama.

Sweeney became the face of Laneige’s “Water Bank” skincare collection in 2022, the Amorepacific-owned brand’s first American celebrity partnership, and the same year began a long-running relationship with Miu Miu as the face of the Miu Wander bag. That collaboration has continued to evolve, and by autumn 2025 Sweeney was headlining Miu Miu’s Paris Fashion Week campaign in a harder-edged, biker-inspired direction, a shift Grazia described as a deliberate departure from the softer aesthetic of her earlier work with the brand.

Beyond fashion and beauty, Sweeney has taken on a wide range of sponsorship work, including partnerships with Armani Beauty, the haircare brand Kerastase, the car manufacturer Ford and the personal-care company Dr. Squatch, alongside a fashion collaboration with American Eagle. Sweeney has said publicly that this endorsement income underpins her lifestyle in Los Angeles more directly than her acting fees alone.

Sweeney co-founded the production company Fifty-Fifty Films in 2020, initially alongside then-partner and producer Jonathan Davino, building a slate that includes “Anyone But You”, “Immaculate” and “Christy”. Following her separation from Davino, Sweeney’s team filed paperwork in January 2026 to reincorporate the company as Fifty-Fifty Films, Inc., with Sweeney listed as chief executive, chief financial officer and secretary, giving her sole control of the venture.

In June 2026, Sweeney launched a second production banner, Honey Trap, together with longtime creative collaborator Kaylee McGregor, securing a first-look deal with Sony Pictures that requires any project the company develops to be offered to the studio first. Deadline reported that the new label is expected to focus on bold, character-driven film and television projects, building on Sweeney’s existing relationship with Sony through titles including “Anyone But You”.

Sweeney has also moved into consumer products, launching the lingerie brand Syrn in January 2026 with venture backing from Coatue Management, offering forty-four sizes designed around fit and comfort rather than occasion wear.

Sweeney’s most significant property purchase to date is a $13.5 million estate in the Florida Keys, known as Tarpon Ranch, roughly thirty minutes from Key West. The compound includes six bedrooms, eight bathrooms, a 520-bottle wine room, a home gym, a games room and a 330-gallon aquarium, and was reported in detail by the Miami New Times at the time of the sale.

In Los Angeles, she owns a Tudor-style home purchased for around $3 million in 2021 and a Bel Air mansion bought for $9.3 million in 2022, and has also sentimentally purchased a modest former home that once belonged to her grandmother. Together, her Californian and Floridian properties make up the bulk of a real estate portfolio built almost entirely from her acting and endorsement income.