Chronic complex illness/multimorbidity is a leading cause of death worldwide. Many people with chronic complex illnesses die in hospital, with the overall quality of end-of-life care requiring substantial improvement, necessitating an increase in the knowledge of the health professionals caring for them. End-of-Life-Essentials (EOLE) offers online education modules for health professionals working in acute hospitals, including one on chronic complex illness. A quantitative pre-post-evaluation analysis was undertaken on data from learners (n = 1489), who completed a questionnaire related to knowledge gained from module completion between December 2018 and November 2019. A qualitative post-evaluation analysis was also conducted using data on learner responses to a question posed between May and November 2019. Results showed a significant positive impact on learners' knowledge, skill, attitude, and confidence in providing end-of-life care to patients living with chronic complex illness. The majority (82.9%, n = 900) intended to change their practice after module completion. A total of n = 559 qualitative comments were analysed thematically, with three major themes emerging: Patient centred care and care planning, Discussion of prognosis, and Valued communication skills. This evaluation has demonstrated that healthcare professionals could benefit from this education to improve quality of care of the dying.