BackgroundDesign thinking is an iterative process that innovates solutions through a person‐centric approach and is increasingly used across health contexts. The person‐centric approach lends itself to working with groups with complex needs. One such group is families experiencing economic hardship, who are vulnerable to food insecurity and face challenges with child feeding.ObjectiveThis study describes the application of a design thinking framework, utilizing mixed methods, including co‐design, to develop a responsive child‐feeding intervention for Australian families—‘Eat, Learn, Grow’.MethodsGuided by the five stages of design thinking, which comprises empathizing, defining, ideating, prototyping, and testing. We engaged with parents/caregivers of a child aged 6 months to 3 years through co‐design workshops (n = 13), direct observation of mealtimes (n = 10), a cross‐sectional survey (n = 213) and semistructured interviews (n = 29). Findings across these methods were synthesized using affinity mapping to clarify the intervention parameters. Parent user testing (n = 12) was conducted online with intervention prototypes to determine acceptability and accessibility. A co‐design workshop with child health experts (n = 9) was then undertaken to review and co‐design content for the final intervention.ResultsThrough the design thinking process, an innovative digital child‐feeding intervention was created. This intervention utilized a mobile‐first design and consisted of a series of short and interactive modules that used a learning technology tool. The design is based on the concept of microlearning and responds to participants' preferences for visual, brief and plain language information accessed via a mobile phone. User testing sessions with parents and the expert co‐design workshop indicated that the intervention was highly acceptable.ConclusionsDesign thinking encourages researchers to approach problems creatively and to design health interventions that align with participant needs. Applying mixed methods—including co‐design— within this framework allows for a better understanding of user contexts, preferences and priorities, ensuring solutions are more acceptable and likely to be engaged.