Tebow moved toward the unconscious man and his family, then led a group of passengers in prayer, according to passenger Richard Gotti.
Medical workers met the flight at the gate when it landed at its destination in Phoenix. The man survived.
The company said that it did not know exactly when during the flight the emergency occurred and that the flight crew consulted with a team of doctors on the ground and decided that the safest option was for the plane to complete its trip to Phoenix.
Flight 1772 originated in Atlanta and carried 177 passengers, two pilots and four flight attendants.
ABC News' Jeffrey Cook contributed to this report.