Roberts began modeling in around 2000, when she started modeling for many agencies, most notably Elle, Vogue and Glamour.
She signed on to be Biotherm, a skin care brand's official model, she gained even more popularity and modeled for many famous agencies such as Ralph Lauren, Gap and even Victoria's Secret.
She started acting with her first film called "Simone" in 2002, with Al Pacino. The studio attempted to keep her identity a secret during production, and did not accord her credit in the initial theatrical release.
She appeared in the series CSI: Crime Scene Investigation as Karen Chevera in the episode "Unplugged" (2012). She played Soul Fleur in the 2013 movie The Host. Roberts appeared on Mad Men opposite Jon Hamm in the episode "Tale of Two Cities". She starred in Rihanna's music video "Bitch Better Have My Money" which was released on July 2, 2015 and was also cast as Cassandra in Andre Niccol's upcoming sci-fi thriller film Anon.
- Many rumors and sites speculated Lily Rabe would portray Sharon Tate, however, once the episode aired, Rachel Roberts was credited in the role.