After a clerkship for U.S. District Court Judge Frederick Lacey, Tom spent two years at Sullivan & Cromwell in New York where he represented not only large corporate clients, but also Haitian refugees seeking asylum in the U.S. He litigated one of the first cases to obtain reversal of an INS exclusion order by an administrative law judge.

In 1983, Tom went to work in Seattle for the Dept. of Justice as an Assistant U.S. Attorney, where he specialized in complex fraud cases. His record as a litigator was extraordinary; in over 18 years, he never lost a case he tried. He became Senior Litigation Counsel and was the first and longest-serving Professional Responsibility Officer at the Seattle U.S. Attorney's Office. As his colleague Bob Westinghouse put it, "His ethical meter seemed to be calibrated just a bit finer than anyone else's."

On seeing a steady stream of prosecutions of bank employees and the ensuing harm to their lives and careers, he set up a program to prevent the crimes before they could occur. Under the program, Tom, along with people convicted of embezzlement, would address groups of new bank trainees to warn them of the consequences of giving in to the frequent temptations of their job.

He taught trial advocacy and lectured on prosecutorial ethics at the Attorney General's Advocacy Institute in Washington, D.C.

Initially, it seems contradictory that a person who had such a sensitivity for fairness and such compassion for defendants would pursue a career as a prosecutor, but it makes perfect sense. He never had to defend a guilty person, and he never had to prosecute an innocent one. He could use the discretion available to him as a prosecutor to bring more fairness to justice. At least one defendant he successfully prosecuted wrote him years later to thank him his compassion and understanding.