Families are coregulating systems in which the daily experiences of 1 member affect the well-being of another member of the family. We examined daily, microdevelopmental processes by modeling the associations between adolescents’ daily problems and emotional experiences in managing Type 1 diabetes and changes in parental negative and positive affect surrounding the illness. Using a daily diary method, 161 mothers (M age = 40 years), fathers (M age = 42 years), and early adolescents (M age = 12.4 years) rated their negative and positive emotions surrounding diabetes for 14 days. Adolescents reported, via a checklist, the number of problems they experienced in managing diabetes each day. Using dynamical systems modeling, we found that adolescents’ problems and emotions were related to changes in their parents’ reports of negative affect, though differently for mothers and fathers. On days when adolescents reported more problems, father’s affect changed more slowly back to homeostasis. Adolescents’ problems were not associated with change in mother’s negative affect, but when adolescents reported greater negative daily affect, mothers were drawn to greater negative affect, displaying a higher set point. Models accounting for parental coupling effects suggested that when adolescents reported more negative affect, mother’s affect changed more slowly back to homeostasis. Neither adolescents’ problems nor their emotions were associated with changes in mother’s or father’s reports of daily positive affect. These results indicate different temporal patterns in mother’s and father’s negative affect that illustrate how mothers, fathers, and adolescents react differently to chronic illness within the family system.