The last decade has been marked by rapid educational change (OECD, 2005), with a renewed focus on teacher accountability. Research has shown that excellence in teaching is the single most powerful influence on student achievement (Hattie, 2003); however, while some teachers 'survive and flourish, others fall by the wayside' (Day and Gu, 2010, p. 1). It is vital, therefore, to be able to understand the conditions that determine the difference. Yet research into the working lives of mid-career teachers, defined as teachers with between 8 to 15 years teaching experience, who are a significant and experienced part of our teaching population, has until recently, been limited. This Australian study investigates broad themes relating to the motivations and concerns of mid-career teachers in NSW Department of Education and Communities (NSW DEC)1 primary schools. Using the Delphi method (Skulmoski, Hartman and Krahn, 2007), 32 statements of key motivations and concerns for mid-career teachers were found, revealing that mid-career teachers are motivated by professional ideals, beliefs and values but are concerned by more practical issues that block their achievement. Knowledge gained from this Delphi study provides a new educational lens through which to view the work of highly professional, mid-career teachers, with implications for educational leadership.