Salvor Harding was the first Mayor of Terminus, the planet which hosted the First Foundation. While technically the planet was under the leadersip of the Encyclopedists who were were working on Encyclopedia Galactica, the planet also had a mayor for civil affairs, mostly due to the increase in the planet's population, as well as the increase in the number of people involved in non-Encyclopedia related affairs.
Hardin is encountered only in Foundation, and is an important character not only because he shapes must of the First Foundation's early history, but also because he faces the first two Seldon crises - crises Hari Seldon had predicted thanks to psychohistory and had prepared holographic messages addressing them.
Little is known of Hardin's childhood of early life. All we know is that he was one of the few on the Terminus who actually studies some rudimentary Psychohistory under Alurin, the only psychologist who was allowed to stay on Terminus after its foundation. However, realizing that he was more suited for politics, he changed expertise and soon became the first mayor of Terminus. However, at least initially, his powers as mayor were mostly emblematic, as Terminus was run by the Council of Encyclopedists. Still, he was ardent in his belief that the people of Terminus, most of whom were not involved in the creation of Encyclopedia, deserved fair representation. At this time, the whole of Terminus still believed that their only purpose was to compile Encyclopedia Galactica. Harding, seen as a shrewd and ruthless politician, campaigns hard for his demands, and eventually takes over the government of Terminus by the end of the First Seldon Crisis.