Keeping Everyone Safe and Securing Lives by Emergency Readiness Act or the KESSLER Act This bill directs the President to develop a national strategy to ensure the health and safety of the U.S. civilian population in case of catastrophic incidents. Specifically, the President must develop and submit to Congress a strategy to provide for the basic needs of the civilian population that is impacted by catastrophic incidents in the United States; coordinate response efforts with state and local governments, the private sector, and nonprofit relief organizations; promote personal and local readiness and non-reliance on government relief during periods of heightened tension or after catastrophic incidents; and develop international partnerships with allied nations for the provision of relief services and goods. The President must issue a plan to implement and operationalize the strategy. The Department of Homeland Security shall lead a national exercise to test and enhance the operationalization of the implementation plan. The President must provide recommendations for (1) actions that should be taken to prepare the United States to implement the strategy, increase readiness, and address preparedness gaps; and (2) additional authorities that should be considered to more effectively implement the strategy.