[2] A longtime supporter and aide of former Vice President Al Gore, Campbell worked in private law practice in Nashville, Tennessee from 1982 until 1993.
He worked as the deputy campaign manager for legal affairs and the treasurer of Gore's presidential campaign committee from 1987 until 1988, and he also worked as legal counsel to the personnel department during Bill Clinton and Al Gore's 1992–1993 presidential transition.
In 1993, Campbell took a job working for Gore as Deputy Counsel to the Vice President and director of administration.
[3] He had been inactive since he took senior status, meaning that while he remained a federal judge, he no longer heard cases or participated in the business of the court.
Campbell died of the effects of multiple system atrophy on April 11, 2021, having suffered from the syndrome for numerous years.