Background: The research explored parents' role constructions for themselves and other caregivers in promoting physical activity, limiting screen time, and ensuring their young child is not sedentary or restrained for extended periods. Method: Using a qualitative social constructionist epistemological position, 10 mothers and 10 fathers (aged 22–49 years) from different households in South East Queensland, Australia, were interviewed. The interviews were transcribed verbatim and analysed using thematic analysis. Results: Thirteen themes emerged in parents' descriptions of their role, aligning with three of the four key influences on parents' role constructions for involvement in their child's behaviour: beliefs about desired child outcomes, beliefs about who is responsible for the outcomes, and parental behaviours related to the beliefs and expectations. Conclusions: Current findings indicate that parents commonly describe active manifestations of parent role constructions that are conducive to facilitating childhood physical activity‐related behaviours. Because many young Australian children are still not sufficiently active, future interventions should seek to target processes influencing parents' ability to fulfil their constructed roles and translate them into actions, including knowledge and skills, self‐efficacy for helping their child, and developing the ability to manage the mix of demands on their time.