The working hours of lawyers in the US vary depending on the kind of work they are doing and their position in their law firm. Junior associates in large firms may work 15 or more hours per day. Senior partners may put in 6-8 hours, or more or less, depending on age, stamina, and interest. would doubt that any lawyer only works 40 hours a week and some may work around the clock or 80 hours a week. But there's no set time frame that's standard for lawyers.