The job duties of a part-time security officer involve protecting a building, facility, or person. As a part-time worker, you work for less than 40 hours per week. Your duties depend on the needs of your employer. As a security guard, you spend your shift monitoring surveillance and security systems, going on patrol around the property, and contacting the police department if necessary. You may have additional responsibilities depending on where you work. For example, security officers on a college campus may escort students and staff at night, while mall guards respond to shoplifting and help find lost children.