Ebling Mis was considered the greatest psychologist to ever live in the Foundation since the times of Hari Seldon, and had the ability to prove it, as he was working on an attempt to reproduce Seldon's work, even though it could cause perturbations in the Seldon Plan. He was also an irreverent, foul-mouthed old man who loved to mess up with any authority figure he faced, particularly Mayor Indbur III.
His job (with the aid of his many students) allowed him to find out when the Fifth Seldon Crisis would take place, a discovery that was vindicated with Kalgan's declaration of war - only for this discovery to turn out to be technically incorrect because the Mule had suddenly become a spanner into the Plan.
Joining Toran and Bayta Darell in their escape to Haven, he eventually accepted that he had to go to Trantor to find out where the Second Foundation was, so as to warn them of the danger. Unknowingly, upon arrival to Trantor the Mule (disguised as the clown Magnifico Giganticus) artificially boosted his gut feeling, allowing him to make great intuitive jumps at the cost of his health.
In the end, he managed to find out where the Second Foundation was, but Bayta Darell killed him before he could say it, because that would have allowed the Mule to learn the truth.