Answer: workaholic

AnswerCrossword Clue
WORKAHOLICHe sleeps with his briefcase
WORKAHOLICNonstop doer
WORKAHOLICPerson who doesn't know when to quit
WORKAHOLICSleep-deprived employee, maybe
WORKAHOLICEmployee who rarely takes off
WORKAHOLICNine-to-niner
WORKAHOLICNine-to-niner, e.g.
WORKAHOLIC9-to-9er
workaholicA person who compulsively works hard and long hours
workaholicone who is excessively fond of work