Girl Talk had a similar "dual life" experience at the start of his career where he was working as a biomedical engineer during the days in a cube farm and jetting off to Europe on the weekends to do gigs.
Jim Eno, from Spoon, was a semiconductor chip designer up until Spoon released Gimmie Fiction. They released four albums before Gimmie Fiction and had multiple international tours.
Here's an early interview: http://pitchfork.com/features/interviews/6415-girl-talk/