Officer De Facto Law and Legal Definition

The term means "an officer de facto is one whose acts, though not those of a lawful officer, the law, upon principles of policy and justice, will hold valid so far as they involve the interests of the public and third persons, where the duties of the office were exercised:

First. Without a known appointment or election, but under such circumstances of reputation or acquiescence as were calculated to induce people, without inquiry, to submit to or invoke his action, supposing him to be the officer he assumed to be.

Second. Under color of a known and valid appointment or election, but where the officer had failed to conform to some precedent requirement or condition, as to take an oath, give a bond, or the like.

Third. Under color of a known election or appointment, void because the officer was not eligible, or because there was a want of power in the electing or appointing body, or by reason of some defect or irregularity in its exercise, such ineligibility, want of power, or defect being unknown to the public.

Fourth. Under color of an election or appointment by or pursuant to a public unconstitutional law, before the same is adjudged to be such." In re Rochester Sanitarium & Baths Co., 222 F. 22, 28 (2d Cir. N.Y. 1915).