Section 703(a)(1) of Title VII of the Civil Rights Act of 1964 (the Act), 42 U.S.C. § 2000e-2(a)(1), prohibits employers from firing an employee based on the employee’s religion. In 1972, Congress amended Title VII of the Act to require that employers also make reasonable accommodations for an employee’s religious practices and observances. Title VII also provided that seniority and merit-based systems were permissible, as long as the systems did not discriminate based on religion. Larry Hardison (plaintiff) was an employee for Trans World Airlines, Inc. (TWA) (defendant), in TWA’s stores department in Kansas City. The stores department operated 24 hours per day and needed to be fully staffed at all times. TWA employees were scheduled based on a seniority system in which employees bid on shifts, with the most senior employees having the first choice of shift assignments. The seniority system was negotiated in a collective-bargaining agreement between TWA and the employees’ union. During his employment with TWA, Hardison joined the Worldwide Church of God, which required Hardison to observe the Sabbath between sunset on Friday and sunset on Saturday. Thus, Hardison was unable to work any shifts during those times. TWA refused to accommodate Hardison’s request not to be scheduled to work during the Sabbath and fired Hardison when he refused to report for work during those shifts. Hardison sued TWA for violating § 2000e-2(a)(1). The district court found in favor of TWA. The court of appeals reversed, ruling that TWA had failed to reasonably accommodate Hardison’s religious practice. TWA petitioned the United States Supreme Court for certiorari.