Reporting directly to Nick Gill, the executive creative director, she will be responsible for creative on a number of major BBH accounts, as well as working on specific briefs and new-business pitches.
While at Mother, Bardales worked on accounts such as Coca-Cola, Egg, Boots and Armani Jeans.
She was also the lead creative on the PG Tips business and was responsible for reinventing Al & Monkey, the former ITV Digital characters, for the tea brand.
Gill said: "She's very interested in the business problem behind the ad problem, and that is what we're trying to set up here, so she is ideal for us. She also has an irreverence about her, which will make her an exciting addition."
Before joining Mother, Bardales worked at Cliff Freeman in the US.
She said: "I chose to join BBH because of the great work that it has done in the past and present, but also for its dedication to the pursuit of producing great work in the future."