Under U.S. law, a conservatorship results from the appointment of a guardian or a protector by a judge to manage the personal or financial affairs of another person who is incapable of fully managing their own affairs due to age or physical or mental limitations. A person under conservatorship is a "conservatee", a term that can refer to an adult. A person under guardianship is a "ward", a term that can also refer to a minor child. Conservatorship may also apply to corporations and organizations.

The conservator may be only of the "estate" (financial affairs) but may be also of the "person", wherein the conservator takes charge of overseeing the daily activities, such as healthcare or living arrangements of the conservatee. A conservator of the person is more typically called a legal guardian. In 2021, an estimated 1.3 million people in the U.S. were under conservatorship.

A person appointed to manage affairs is a conservator. A person under conservatorship is a conservatee. Under a guardianship, the appointed person is a guardian and subject person is a ward. When referring to government control of private corporations, conservatorship implies a more temporary control than does nationalisation.

Some jurisdictions, such as California, distinguish between conservatorship of an adult as compared to an unemancipated minor. Within such a jurisdiction, a person who is under what is more typically described as a guardianship may be described as a "conservator of the person". Other jurisdictions, such as New York, use the term guardianship in both contexts.

A "limited conservatorship" usually refers to the limited legal responsibilities of a conservator over the affairs of an individual who is developmentally disabled, but still capable of making important decisions for themselves. In these cases, the conservatee to whom the limited conservatorship applies can retain more control over their personal affairs than other conservatees can; for example, they may retain their right to decide where they may live.

Conservatorship is established either by court order (with regard to individuals) or via a statutory or regulatory authority (with regard to organizations such as business entities). In other legal terms, a conservatorship may refer to the legal responsibilities over a person who has a mental illness, including individuals who are psychotic, suicidal, demented, incapacitated, or in some other way unable to make legal, medical or financial decisions on behalf of themselves.

Conservatorship is a legal term referring to the legal responsibilities of a conservator over the affairs of a person who has been deemed gravely disabled by the court and unable to meet their basic needs of food, clothing, and shelter. They are governed by the state's individual laws. Terminology varies, and some states or jurisdictions may refer to a conservator as a guardian of the estate or as a trustee.

Conservatorships are generally put in place for people who are significantly disabled by mental illness, elderly individuals who lack mental capacity due to medical conditions such as dementia, or individuals with developmental disabilities who lack the capacity to manage their own affairs. In typical conservatorship proceedings, an allegedly mentally incapacitated person must be evaluated by a qualified physician or psychiatrist who prepares a report documenting the person's mental capacity that is provided to the court and may be used as evidence.