Background: Fathers are increasingly acknowledged as active participants in rearing young children, yet few observational measures recognize gender-differentiated parenting and can be used by practitioners and researchers to assess and improve fathers' parenting capacity in playful settings, in order to inform program effectiveness. Two potential measures are the Rough-and-Tumble Play Quality Scale (RTPQ), which is based on evolutionary and attachment theory and assesses rough-and-tumble play behaviors related to social-emotional competencies. The second is Dads' Parenting Interaction with Children: Checklist of Observations Linked to Outcomes (PICCOLO-D), which is grounded in a systemic approach linking parenting behaviors to child outcomes. Objective: The aim of this study was to compare the two observational measures for suitability of assessment of fathers' parenting capacity with diverse low-income families. Method: A correlational longitudinal design was used to examine naturalistic rough-and-tumble play extant video observations of 25 fathers and their 2- to 4-year-old children independently coded with each measure, with child prekindergarten and fifth grade outcomes. Results: Convergent validity showed strong association between the two measures. No associations were found with family characteristics. Both measures predicted child prekindergarten attention regulation and aggression (inversely). PICCOLO-D predicted prekindergarten language and cognition, and language/literacy in fifth grade. Conclusions: The similarities and subtle differences between the measures confirm the distinctive theoretical approaches underpinning each measure, and suggest both are suitable tools for practitioners and researchers. PICCOLO-D may be useful for multiple type of play, while the RTPQ may be more relevant to specific qualities of paternal physical play interaction.