The challenge of improving the performance of students with diverse needs and abilities has concerned teachers throughout the history of modern education. However, not until the accountability measures instituted by the No Child Left Behind (NCLB) Act of 2001—requiring disaggregating the results of all subgroups of learners, by ethnicity, socio-economic status, pupil services, and English language proficiency—has this challenge of reaching out to every student that needs attention been brought to the public's focus. This progressive facet of the law has been a positive driving force in Balasubramanian's research agenda. As scholar-teacher, this portfolio dissertation describes Balasubramanian's ongoing efforts to consistently increase student learning and achievement as he continues to work in high-needs secondary schools—schools with large populations of students from low-income, migrant, and international families—by focusing on student motivation, engagement, and cognition. All five studies described here have shown significant normalized gains. These gains demonstrate the increase in standards-based content knowledge of learners across all levels due to specific instructional interventions. The effect sizes of the observed means across all the studies were high.