"It's what I do that defines me."

My father works as a financial systems specialist in the McGraw-Hill company. While he basically is the image of "an office worker in a cubicle working for coporate America," he has defined himself in ways that do not include his job. For instance, though he is an office worker, his skills as a guitarist and woodworker (both of which he does in his free time) can also be recognized by friends and family. In the case of someone like my father, work is just a part of his or her personality, not the majority of it.

However, some individuals have based their entire lives around their work. For example, without the success of the Harry Potter series, I doubt anyone would be able to recognize J. K. Rowling's name. The individuals who have made a name for themselves often have done so because of the success of their jobs. It is impossible to tell if work will define a person, but if it is the thing that brings the individual success, his job is almost guarenteed to be his new identity.