Background: To help caregivers manage the unique demands of providing care for someone who has been diagnosed with cancer, we developed a brief self-determination theory-based eHealth intervention to increase caregivers' self-care behaviours (operationalized as physical activity and fruit and vegetable consumption). Using a mixed-methods approach, the main objective of this study was to assess the feasibility and acceptability of our intervention. Methods: Our intervention included 4 weekly one-on-one autonomy supportive interactive video-calls with a health and wellness advisor. Quantitative data were collected pre- and post-intervention and analyzed descriptively. Semi-structured interviews were conducted post-intervention and analyzed using thematic analysis. Results: From January to June 2019, 7 caregivers (Mage=63.9, SD=12.2, 71.4% female) were recruited via community organizations, social media, and word of mouth. Recruitment/enrollment (53.8%) was low; however, adherence (100%), fidelity (99%), and retention (100%) rates were high after enrollment. Participants generally expressed satisfaction with the intervention content, delivery mode, frequency, personalized approach, and support received from the advisor, though some desired more sessions over a longer period of time. Three themes captured caregivers' experiences within the intervention: (1) building and maintaining supportive relationships; (2) refocusing on self-care; and (3) engaging in self-care to be a better caregiver. Conclusions: Individually tailored interventions may empower cancer caregivers to prioritize self-care and focus on their own social, emotional, and physical health, and in turn enhance their ability to provide care. Co-designing recruitment strategies with caregivers and partnering with organizations who provide services to cancer survivors and caregivers may facilitate recruitment for future interventions.