| 1961-1965 | sales clerk, stockboy, etc | Drexelbrook Pharmacy |
| door-2-door sales (pens, bulbs) | self employed | |
| 1966-1967 | sales clerk, stockboy, etc | Boysville (apparel) |
| amateur sports photographer | Drexel Hill Jr High School | |
| 1968-1969 | apprentice, prop maser, tent tech | John B Kelly Playhouse in the Park |
| waiter | City Line Delicatessen | |
| mowing lawns | self employed | |
| driveway salesman | City Line Esso | |
| pizza delivery | Boston Style Pizza | |
| plant nursery work | Albrecht's | |
| 1970 | police work (education field experience) | Lower Merion Police Department |
| drama club (president) | Lower Merion High School | |
| volunteer fireman | Elkins Park Fire Company #3 | |
| pizza delivery | Northeast Pizza | |
| Polster | Exxon | |
| piecework in hippy leather accessories | M&M enterprises | |
| 1971 | protester/organizer/chairman | Ogontz Mobilization Committee to End the War |
| 1972-73 | dishwasher, busboy, waiter | Toftrees Resort |
| dishwasher, busboy, waiter | Dante's Restaurant (Zangrilli Enterprises) | |
| produce delivery | Zangrilli Enterprises | |
| piemaker | Hi-Way Pizza (Zangrilli Enterprises) | |
| sandwich maker/delivery | Village Sub Shop | |
| maintenance/landscaping | Penn State University Maintenance | |
| dishwasher, busboy, counter, banquet waiter | Penn State University Food Service | |
| 1973-74 | furniture assembly/delivery, carpet installation | Bellefonte Furniture |
| roadie/ferris wheel operator | Garbrick Amusement | |
| truck driver | Pleasant Gap Stone Quarry | |
| bus driver | Fullington Autobus | |
| factory worker | Boalsburg Canning Factory | |
| 1975 | driveway salesman | City Line Esso |
| co2 delivery/maintenance | Carbonator Rental Service | |
| waiter | Philadelphia's Locust Club | |
| driveway salesman | Princeton Exxon | |
| surgeons' assistant | Princeton Medical Center | |
| class photographer, tutor to disturbed teenager | Hahneman Medical College & Hospital | |
| research assistant | Temple University School of Medicine | |
| 1976 | research assistant | University of Arizona Microbiology |
| 1977 | computer consultant | University of Arizona Biochemistry |
| 1978-1983 | member technical staff | Bell Labs - Loop Transmission |
| 1983-1989 | member technical staff | Bellcore - Computer Science Research |
| 1989-1991 | member technical staff | D.E. Shaw & Co. |
| 1993-2001 | associate/vice president/executive director | Morgan Stanley |
| 2001-present | hacking for fun | self |