Guided by its First to the Top legislation enacted in early 2010, Tennessee is one of the first States to implement a comprehensive teacher evaluation system based on multiple measures of teacher performance. Full implementation began in the 2011-2012 school year. Similar to other States engaged in rethinking teacher evaluation systems, Tennessee is aiming to make evaluations of educators more reflective of effective instruction, more attentive to student learning, more diagnostic and more informative for making human resources decisions. This paper describes Tennessee's transition to the Teacher Educator Acceleration Model (TEAM) and illustrates implementation challenges and lessons learned.