In the past decade, a new wave of writing assessment tools has evolved as a result of advances in computer technology, highlighting the potential of automated writing evaluation (AWE) tools in the English as a second language (ESL) writing programs and comprising a concerted effort to move from use of AWE tools for testing to teaching. Today's innovative AWE tools offer ESL instructors promising solutions for providing immediate feedback and meeting the demands for better practices in the digital age. However, the outcomes of using AWE are not free of challenges (Chen & Cheng, 2008; Wang, Shang, & Briody, 2012) and necessitate a comprehensive understanding about how to effectively integrate AWE and improve students' writing (Ware, 2011). In situ studies are, therefore, necessary to identify the ways in which teachers are incorporating AWE into their classrooms in order to provide an insight into best practices. This longitudinal qualitative study investigates the practices and perspectives of five university-level writing instructors as they meet challenges and possibilities of using AWE in seven ESL writing courses. Data collection included observations, individual interviews, and delayed focus group interviews. In this paper, we highlight ESL instructors' teaching strategies, perception of the effectiveness, satisfaction, and concerns with the AWE tool (Criterion) they employed. We also describe changes in strategies and perceptions after a second semester of using the AWE tool. We conclude with final suggestions for best practices for integration of AWE into the ESL curriculum. Our research intends to expand the current knowledge of AWE by outlining appropriate and effective implementation of AWE technologies.