To become a professional tennis umpire, you must complete training and certification requirements at a program accredited by either the International Tennis Federation (ITF), the world governing body of tennis, or the United States Tennis Association (USTA). Both governing bodies have the same standards and official rules that they require prospective umpires to know thoroughly. The duties of a tennis umpire depend on whether they are assigned as the chair umpire, net umpire or line umpire. In addition to these on-court umpires, a head referee will be assigned to an event as the final authority on questions of tennis law and as a mediator if disputes cannot be resolved by the chair umpire. A chief umpire is also usually brought in to schedule assignments and evaluate the performance of court officials.
According to the USTA, the chair umpire is the final authority on all questions of fact during the match. The chair umpire is the most visible official on the court, sitting in a raised chair by the net. Chair umpires have the right to overrule calls made by line or net judges if they are sure a mistake has been made; however, the call must be overruled immediately after the mistake is made and never as the result of player protest. Play can be stopped or suspended at any time it is deemed necessary by the chair umpire such as in cases of darkness or bad weather. Manual inspections of ball marks can be granted on clay courts only.
Line and Net Umpires
Line umpires are in charge of juding whether a ball is in or out and determining if a service foot fault has been committed. Line umpires must be in the best possible position to make accurate calls. They are allowed to make calls on balls or faults on their assigned lines only. Line officials also go with players on toilet or change of attire breaks to make sure no violations occur. If a call is questionable, line umpires must inform the chair umpire, who will make the final decision. Net umpires rule on calls relating to service faults.
A chief umpire does not perform on-court duties but acts more as an administrator. Chief umpires must recruit an adequate number of trained officials for the tournament, conduct training and review official rules with umpires prior to the tournament and schedule court assignments. They also act as an assistant to the head referee and are in charge of evaluating performances for all on-court officials.