Sohn started his career with Pixar in the art and story departments for Finding Nemo. He also worked on The Incredibles, Ratatouille and WALL-E. Sohn also performed the voice of Emile in Ratatouille. He made his directorial debut with the short film Partly Cloudy in 2009 which he also wrote. Partly Cloudy was included in the Animation Show of Shows in 2009. Sohn co-directed the English-language version of Ponyo on the Cliff by the Sea in 2009 with John Lasseter and Brad Lewis.