Opportunities for part-time or summer work as security guards are not generally available to high school students. You may, however, work as a lifeguard, on a safety patrol, and as a school hallway monitor, which can provide helpful experience. Another way to explore the field is to conduct an informational interview with a security guard. Ask your school's career services office for help with setting this up, and prepare a list of questions in advance.

Security guards have various titles, depending on the type of work they do and the setting in which they work. They may be referred to as patrollers (who are assigned to cover a certain area), bouncers (who eject unruly people from places of entertainment), golf-course rangers (who patrol golf courses), or gate tenders (who work at security checkpoints).

Many security guards are employed during normal working hours in public and commercial buildings and other areas with a good deal of pedestrian traffic and public contact. Others patrol buildings and grounds outside normal working hours, such as at night and on weekends. Guards usually wear uniforms and may carry a nightstick. Guards who work in situations where they may be called upon to apprehend criminal intruders are usually armed. They may also carry a flashlight, a whistle, a two-way radio, and a watch clock, which is used to record the time at which they reach various checkpoints.

Guards in public buildings may be assigned to a certain post or they may patrol an area. In museums, art galleries, and other public buildings, guards answer visitors' questions and give them directions; they also enforce rules against smoking, touching art objects, and so forth. In commercial buildings, guards may sign people in and out after hours and inspect packages being carried out of the building. Bank guards observe customers carefully for any sign of suspicious behavior that may signal a possible robbery attempt. In department stores, security guards often work with undercover detectives to watch for theft by customers or store employees. Guards at large public gatherings, such as sporting events and conventions, keep traffic moving, direct people to their seats, and eject unruly spectators. Guards employed at airports limit access to boarding areas to passengers only. They make sure people entering passenger areas have valid tickets and observe passengers and their baggage as they pass through X-ray machines and metal detection equipment.

After-hours guards are usually employed at industrial plants, defense installations, construction sites, and transport facilities such as docks and railroad yards. They make regular rounds on foot or, if the premises are very large, in motorized vehicles. They check to be sure that no unauthorized persons are on the premises, that doors and windows are secure, and that no property is missing. They may be equipped with walkie-talkies to report in at intervals to a central guard station. Sometimes guards perform custodial duties, such as turning on lights and setting thermostats.

In a large organization, a security officer is often in charge of the guard force; in a small organization, a single worker may be responsible for all security measures. As more businesses purchase advanced electronic security systems to protect their properties, more guards are being assigned to stations where they monitor perimeter security, environmental functions, communications, and other systems. In many cases, these guards maintain radio contact with other guards patrolling on foot or in motor vehicles. Some guards use computers to store information on matters relevant to security such as visitors or suspicious occurrences during their time on duty.

Security guards work for government agencies or for private companies hired by government agencies. Their task is usually to guard secret or restricted installations domestically or in foreign countries. They spend much of their time patrolling areas, which they may do on foot, on horseback, or in automobiles or aircraft. They may monitor activities in an area through the use of surveillance cameras and video screens. Their assignments usually include detecting and preventing unauthorized activities, searching for explosive devices, standing watch during secret and hazardous experiments, and performing other routine police duties within government installations.

Security guards are usually armed and may be required to use their weapons or other kinds of physical force to prevent some kinds of activities. They are usually not, however, required to remove explosive devices from an installation. When they find such devices, they notify a bomb disposal unit, which is responsible for removing and then defusing or detonating the device.