She grew up in Ketchum, Idaho, and attended Ernest Hemingway Elementary School. She later moved to California and lived in the Westlake Village. She attended Oaks Christian High School for two and a half years and then dropped out to pursue her modelling career. She was presented as a debutante at the Bal des débutantes in Paris, France in 2003.
In March 2009, she debuted at the fall/winter 09–10 catwalk show for Givenchy in Paris. In June 2009, she walked in the Calvin Klein resort show in New York. In September 2009, she opened the Topshop spring/summer 2010 show in London.
In January 2010, she became the new face of the Gianfranco Ferré advertising campaign. Later that year, she fronted a new advertising campaign for the Salvatore Ferragamo perfume Attimo.
She was photographed by Bryan Adams for the spring 2011 issue of Zoo Magazine.
Hemingway followed in her mother and aunt's footsteps by launching her acting career. She has appeared predominantly in independent films. Her first lead role was in the independent film Starlet (2012), directed by Sean Baker. She, along with the rest of the cast, was awarded the Robert Altman Award for the film at the 2012 Independent Spirit Awards. She has since had supporting roles in films such as Listen Up Philip (2014) and While We're Young (2014) and leading roles in The People Garden and Live Cargo, the latter of which premiered at the 2016 Tribeca Film Festival.
Hemingway is the Playboy Playmate in the March 2016 issue of Playboy, making her a second-generation Playboy model.
In 2017, Hemingway appeared in Michelle Morgan's It Happened in L.A., which premiered at the 2017 Sundance Film Festival, as well as Russell Harbaugh's Love After Love, which premiered at the 2017 Tribeca Film Festival. Her upcoming films include 7x7, In a Relationship, Wanderland, Run With the Hunted, The Unicorn, and Violet.
