The FITNESS Act establishes uniform eligibility standards for federal law enforcement officers, requiring candidates to be U.S. citizens aged 21-36 with either a bachelor's degree or a high school diploma plus four years of work experience, along with passing medical exams, drug tests, background investigations, and firearms qualifications. The bill prohibits hiring or employing federal officers who have participated in or materially supported hate groups, violent organizations, or groups advocating discrimination based on race, religion, disability, sexual orientation, ethnicity, or gender, and bars current officers from socializing with criminals or joining organizations that compromise their agency's integrity. To enforce these standards, the bill creates the National Law Enforcement Accountability Database to track officer misconduct, terminations, criminal convictions, and commendations, requiring federal agencies to query this database before hiring, transferring, or promoting officers and to report use-of-force incidents within 30 days. The law takes effect 30 days after being signed, though agencies may begin preparatory steps immediately, and agencies must implement all requirements using existing budgets with no new federal funding authorized.