In response to the pandemic-induced economic crisis for U.S. families, the federal government expanded the Child Tax Credit (CTC) via the distribution of monthly payments in the second half of 2021. Studies have found that these monthly payments corresponded with reductions in food insecurity, but what is not yet clear is whether these declines were stable across and within the months of receipt. Using novel, daily survey data among a sample of low-income families at high risk of food insecurity (N = 146), we tested whether the CTC payments were associated with stable rates of day-to-day food security. We found consistent declines in food insecurity across CTC months, though smaller declines for Supplemental Nutrition Assistance Program (SNAP) recipients who experienced lower food insecurity rates, on average. Within a CTC month, we found that food insecurity was stable for non-SNAP families for the first few weeks, but spiked in the week prior to the next payment. SNAP families’ within-month patterns of food insecurity, however, appeared to be tied more to their SNAP benefit timing than CTC payment timing. Both groups saw end-of-the-month spikes in food insecurity among those who received higher CTC amounts, suggesting the money may have been more difficult to stretch across families with a greater number of children. These results suggest that the effectiveness of cash payments like the CTC in reducing economic hardships may depend on family characteristics like receipt of other federal benefits and household size. Accordingly, future provisions of cash assistance may benefit from going beyond income alone and tailoring the amount to a family’s benefits package.