Diversity and Inclusion at the Department of State Act This bill establishes a new position and requires other activities to promote diversity and inclusion in the Department of State. The bill creates the presidentially-appointed position of Chief Diversity and Inclusion Officer in the Office of the Deputy Secretary of State to, among other activities, develop a strategic plan to guide implementation of diversity and inclusion efforts and support State Department personnel from traditionally underrepresented groups. The officer reports directly to the Secretary of State. Additionally, the State Department must establish a Diversity and Inclusion Leadership Council to coordinate applicable strategic plans, initiatives, and policies. The bill also modifies merit selection processes for promotions, performance pay, and related matters to promote diversity and inclusion in the Foreign Service. Specifically, it adds factors (e.g., testimony from peers and subordinates or demonstrated support for diversity and inclusion) that may be considered in recommendations and rankings related to a Foreign Service officer's performance. The State Department must also establish a mentorship program for entry- and mid-level members of the Foreign Service and periodically offer a Senior Executive Service development program to members of the civil service in the top two pay grades. Senior Executive Service members serve as high-level managers within federal agencies. The bill requires the State Department to report on its diversity and inclusion efforts, as well as demographic information about members of boards that make personnel decisions and candidates for the Senior Executive Service.