In Hamilton v. Zimmerman (1857) 37 Tenn. (5 Sneed) 39, the Tennessee Supreme Court decided what is widely regarded as the first judicial estoppel case in the country.
There, the plaintiff, a pharmacist, was a part owner of a pharmacy on the verge of financial ruin. The defendant bought the pharmacy, and the plaintiff continued to work there.
After the defendant sold the business, the plaintiff filed suit for a share of the profits, alleging the parties had formed a secret oral partnership that entitled him to one-half of the proceeds.
The defendant denied the existence of the partnership, contending the plaintiff was employed as a clerk. In support of his defense, the defendant relied on sworn pleadings in earlier litigation between the parties in which the plaintiff had admitted he was a clerk. ( Id. at pp. 46-47.)
The court held that the plaintiff was estopped to pursue his partnership claim, explaining:
"The plaintiff's prior pleading is at least an implied admission of the truth of the statement of the defendant--that the plaintiff was merely his clerk. And for all the purposes of the present complaint, the admission must be taken as true, without inquiring whether, as a matter of fact, it be so or not. The law, as against the plaintiff, presumes that it is true; and this presumption proceeds upon the doctrine of estoppel, which, from motives of public policy or expediency, will not, in some instances, suffer a man to contradict or gainsay, what, under particular circumstances, he may have previously said or done. This doctrine is said to have its foundation in the obligation under which every man is placed to speak and act, according to the truth of the case; and in the policy of the law to suppress the mischiefs from the destruction of all confidence in the intercourse and dealings of men, if they were allowed to deny that, which by their solemn and deliberate acts, they have declared to be true. And this doctrine applies with peculiar force, to admissions or statements made under the sanction of an oath, in the course of judicial proceedings. The chief security and safeguard for the purity and efficiency of the administration of justice, is to be found in the proper reverence for the sanctity of an oath." ( Hamilton, supra, 37 Tenn. at pp. 47-48.)