This document proposes a method for completing user profiles using their online social circles. It introduces the task of user profile completion and discusses how existing approaches do not leverage users' real social circles. The method presented uses non-negative matrix factorization to decompose a circle-profile matrix into a circle-user matrix and user-profile matrix. This allows the model to detect a user's multi-dimensional social characteristics from their various social circles. Experimental results on Facebook, LinkedIn, and Microsoft Academic Search datasets show the approach outperforms state-of-the-art methods for user profile completion.