Workers age 16 or 17. By state law, 16- and 17-year old high school students may not work after 11 p.m.My child wants to get a job. How old must he or she be to work? By state law, 16 and 17yearold high school students may not work after 11 pm on evenings before school days or before 5 am on school days. First, if a 17 year old has graduated from High School, they can work full time and are not subject to the other work restrictions. Minors under the age of 16 may work up to 8 hours a day, 40 hours per week. Work is prohibited between the hours of 9 p.m. 16 - Basic minimum age for employment. No employer shall be permitted to work a minor under the age of 16 more than 40 hours a week or more than eight hours in any 24-hour period.