As modern nursing advances at an astounding rate, existential advocacy (EA) is vital for delivering patient care in line with wellness goals and personal values. This concept analysis aims to define EA within the context of nursing and align the concept with Jean Watson’s Unitary Caring Science (UCS) and her 10 Caritas Processes. A comprehensive literature search identified 12 relevant publications from the following databases: PubMed, PsycINFO, Google Scholar, and CINAHL. Subsequently, utilizing Walker and Avant’s method for concept analysis, a standardized structure to identify EA’s defining attributes, antecedents, consequences, and empirical referents emerged. Antecedents for EA are patient vulnerability, nurse-patient rapport, nurse autonomy to act as an advocate, and patient request for advocacy. Defining attributes of EA include the following: supporting patient self-determination, caring-trusting nurse-patient relationship, promoting individualized meaning of health and wellness, and encouraging values-based problem-solving. The optimal consequence of EA is patients’ awareness of their current health status, leading to individualized care and decision-making based on a patient’s values. EA is a nurse’s effort to support and promote their patients’ right to self-determination by helping them discern their holistic health and wellness situation and then clarify their values within that reality. Watson’s UCS and 10 Caritas Processes align with EA to facilitate nurse-patient transpersonal caring occasions. EA explicates the care and advocacy nurses provide into a defined concept while highlighting nurses’ essential role in patients’ physical, emotional, and spiritual well-being. With EA better defined, the concept can be assessed, measured, and implemented within the discipline of nursing.