Background: The pervasive gap in achievement among impoverished children has been investigated primarily in terms of parental investments, specifically parent to child speech and other forms of cognitive stimulation (e.g., toys, print materials). This research extends that literature by considering the role of a non-cognitive factor, namely task persistence, in the income-achievement gap. Using task persistence as the hypothesized mediator, duration of childhood in poverty is used to predict two educational variables - perceived academic competence and educational attainment. Although bivariate relationships between each of the variables have been demonstrated in past research, a full model linking task persistence with the income-achievement gap has not been investigated thus far. Methods: Using multiple waves of longitudinal data, duration of childhood poverty (ages 0-9) is used to predict both perceived academic competence (age 17) and educational attainment (age 23) with task persistence (average of ages 9, 13, 17) as a mediator. Results: With task persistence included in each model, the relationships between duration of childhood in poverty and both perceived academic competence and educational attainment are significantly reduced, confirming a mediational influence of task persistence. Conclusions: As hypothesized, task persistence statistically mediates the relationship between duration of childhood in poverty and educational outcomes. The implications of these findings on school success and intergenerational poverty are addressed, as well as suggestions for future research.