Young children of mothers with adult attention-deficit/hyperactivity disorder (ADHD) are at risk for ADHD by virtue of genetics and environmental factors. Moreover, parent ADHD is associated with maladaptive parenting and poor child behavioral treatment response. Thus, a combined approach consisting of behavioral parent training (BPT) and maternal stimulant medication (MSM) may be needed to effectively treat ADHD within families. However, providing combined BPT+MSM initially to all families may be unnecessarily burdensome because not all families likely need combined treatment. The purpose of this study is to examine how to combine, sequence, and personalize treatment for these multiplex families in order to yield benefits to both the parent and child, thereby impacting the course of child ADHD and disruptive behavior symptoms. This article presents our rationale for, design of, and preliminary experiences (based on 26 participants) with an ongoing pilot Sequential Multiple Assessment Randomized Trial (SMART) designed to answer questions regarding the feasibility and acceptability of study protocols and interventions. This article also describes how the subsequent full-scale SMART might change based on what is learned in the SMART pilot and illustrates how the full-scale SMART could be used to inform clinical decision making about how to combine, sequence, and personalize treatment for complex children and families in which a parent has ADHD.