Sickle cell disease (SCD) is an inherited hemoglobinopathy that leads to blood vessel occlusion and multiorgan complications, including pain, that may be experienced daily. Symptom management often begins at home, and tools are needed to support self-management strategies that can be implemented by children with SCD and families. The purpose of this study was to assess the feasibility of the mHealth self-management intervention (application) Voice Crisis Alert V2 for children with SCD and families. Feasibility assessment was guided by the Reach, Efficacy, Adoption, Implementation, and Maintenance framework. Data were collected with 60 dyads (children with SCD/caregivers) at four time points. Self-management data were collected via application use, and postintervention interviews were conducted. Analyses included descriptive statistics and constant comparison with directed content analysis. Recruitment was completed in 28 weeks, with 82% retention at end-of-intervention. Mobile Application Rating Scale scores and interview data indicated high satisfaction. From baseline to mid-intervention, 94% of dyads used the application (75% of total use); 45% used the application from mid-intervention to the end-of-intervention. Dyads made 2,384 actions in the application; the most commonly used features were recording health history and recording and tracking symptoms. Few reported issues with the application; most issues occurred early in the study and were corrected. After the intervention period was completed, 37% continued to use the application. Feasibility was confirmed by meeting recruitment and retention goals, high adoption of the application, and high reported satisfaction with the application. Challenges with sustained use were encountered, and areas for improvement were identified.