DHS Field Engagement Accountability Act (Sec. 2) This bill amends the Homeland Security Act of 2002 to direct the Department of Homeland Security (DHS) to develop or update not less frequently than once every five years a strategy for DHS engagement with fusion centers. The term "fusion center" means a collaborative effort of two or more government agencies that combines resources, expertise, or information to maximize the ability of such agencies to detect, prevent, investigate, apprehend, and respond to criminal or terrorist activity. Such strategy shall include: (1) specific goals and objectives for sharing information and engaging with fusion centers, (2) performance metrics for measuring success in achieving such goals and objectives, and (3) a five-year plan for continued engagement with fusion centers. (Sec. 3) DHS shall: (1) consider the effectiveness of existing processes to identify and prepare field personnel for deployment to support fusion centers and internal mechanisms to ensure oversight and accountability of such personnel; and (2) publish and disseminate performance metrics, taking into account regional and threat diversity. DHS shall develop and implement a formalized training module for fusion center personnel regarding the classified Homeland Secure Data Network of DHS, or any successor system. (Sec. 4) DHS shall: (1) develop policies and metrics to ensure effective use by DHS components of the unclassified Homeland Security Information Network, or any successor system; and (2) develop policies for posting unclassified products on the network. DHS shall assess and implement technical enhancements to the network to improve usability, including search functionality, data analysis, and collaboration capabilities. (Sec. 5) DHS must report describing the implementation of: (1) the fusion center information sharing strategy, (2) the deployment of field personnel to fusion centers, and (3) policies that seek to ensure the effective use of the Homeland Security Information Network.