Department of Peacebuilding Act of 2017 This bill establishes a Department of Peacebuilding in the executive branch, to be headed by a Secretary of Peacebuilding, dedicated to peacebuilding, peacemaking, and the study and promotion of conditions conducive to both domestic and international peace and a culture of peace. The bill sets forth the mission of the department, which includes the cultivation of peace and peacebuilding as a strategic national policy objective and development of policies that promote national and international conflict prevention, nonviolent intervention, mediation, peaceful conflict resolution, and structured conflict mediation. There is established in the department: (1) the Office of Peace Education and Training, (2) the Office of Domestic Peacebuilding Activities, (3) the Office of International Peacebuilding Activities, (4) the Office of Technology for Peace, (5) the Office of Arms Control and Disarmament, (6) the Office of Peacebuilding Information and Research, (7) the Office of Human Rights and Economic Rights, and (8) the Intergovernmental Advisory Council on Peace. A Federal Interagency Committee on Peace is established to coordinate the actions of the department with other federal agencies. The Department of Defense and the Department of State must consult with the department concerning nonviolent means of conflict resolution when a conflict between the United States and any other government or entity is foreseeable, imminent, or occurring. The department shall encourage citizens to observe and celebrate the blessings of peace and endeavor to create peace on Peace Days, which shall include discussions of the professional activities and the achievements in the lives of peacemakers.