Developmental researchers seek to understand the processes that contribute to the changes that occur throughout the lifespan. During infancy, toddlerhood, and early childhood, these processes are integral for healthy cognitive development. In the first year of life, one behavior that is commonly observed and measured is attention, and research has established the importance of early attentional behaviors in the development of later cognitive abilities. The First Year Inventory (FYI) was designed to identify 12-month olds at risk for an eventual diagnosis of autism spectrum disorder (ASD). Preliminary research created three attention-based constructs (responding to attention coordination, initiating attention coordination, and sensory and attentional engagement) derived from the FYI items as a novel way to use this measure in developmental research. The current study was designed to examine the predictive value of these three attention constructs in regards to patterns of the development of attentional and executive control between 30 and 42 months of age. Four subgroups were identified on the basis of individual differences in both the 30-month scores and the rate of change between 30 and 42 months. These subgroups represented distinct developmental trajectories, and group placement was predicted by 12-month attentional behaviors. The relation between parent-reported 12-month attention and 42-month executive function was explored, analyzing the moderating effect of attentional control subgroup. Findings suggest that the pattern of development between 30 and 42 months affects the strength of the relation between early attentional behaviors and aspects of executive function in early childhood. Lastly, parent-reported executive function behaviors were compared to laboratory assessments of the same constructs. Although analyses revealed little to no relation between these distinct measurements, the lack of findings points to potential concerns regarding methodology commonly used to measure these cognitive constructs in early childhood. Overall, these findings help to fill a gap in our understanding of early childhood cognitive development and illustrate the value of examining individual trajectories, as opposed to one or more independent time points.