Derived Judicial Immunity
Derived judicial immunity extends a judge's absolute immunity to non-judges who act as an arm of the court. Texas applies a functional test, asking whether the person exercised discretion comparable to a judge's in performing an assigned judicial function. Court-appointed receivers, guardians ad litem and similar appointees are the usual claimants. Purely ministerial work does not qualify.
Judges cannot be sued for judicial acts. Neither, in Texas, can certain people the court appoints to do part of the judge's work, and the reason is the same. A person exercising judgment on the court's behalf should not have to weigh the risk of personal liability while doing it.
The functional test
Texas asks what the person was doing, not what title the person held. Immunity attaches where the appointee performs a function that is an integral part of the judicial process and exercises discretion comparable to a judge's. Dallas County v. Halsey, 87 S.W.3d 552 (Tex. 2002), draws the line from the other side. A court reporter preparing the reporter's record was held not entitled to derived judicial immunity, because preparing a record is ministerial or administrative rather than discretionary. The case is worth reading precisely because it denies immunity. Proximity to the court is not enough.
Contrast a guardian ad litem weighing a minor's interests in a proposed settlement. That person exercises the kind of judgment a judge would otherwise exercise, and is ordinarily protected. So is a receiver deciding how to dispose of estate property under an order of appointment.
Once it attaches, it covers the function
The business court addressed the doctrine in Fischer v. Fischer, 2026 Tex. Bus. 54 (8th Div. July 29, 2026), dismissing the claims with prejudice. The formulation matters for how the defense is pleaded. Once derived judicial immunity attaches to a function, every action taken with respect to that function is immune. A plaintiff cannot slice the appointment into good acts and bad acts and sue over the bad ones. The inquiry runs to the function, and it stops there.
That is stronger than plaintiffs expect, and it explains why claims against court appointees are usually resolved at the pleading stage rather than after discovery into what the appointee actually did.
Distinguish attorney immunity
The two doctrines get conflated and they should not be. Attorney immunity protects a lawyer acting for a client, and its source is the lawyer's duty to that client. Derived judicial immunity protects a person acting for the court, and its source is judicial immunity itself. A guardian ad litem is not immune because she is a lawyer. She is immune because the court appointed her to exercise judgment on its behalf. A transactional lawyer advising a board has no derived judicial immunity at all, and a court-appointed receiver who is not a lawyer has no attorney immunity.
The practical difference shows up in scope. Attorney immunity is measured by the scope of the representation. Derived judicial immunity is measured by the scope of the appointment. Where a receiver takes on tasks the appointing order did not cover, the protection thins, and a plaintiff drafting around the immunity will aim at exactly that: conduct the appointment did not authorize.