This article presents findings from a year-long multilevel comparative case study exploring the characteristics of effective urban high schools. We developed a comprehensive framework from the school effectiveness research that guided our data collection and analysis at the four high schools. Using value-added methodology, we identified two higher and two lower performing high schools in Broward County, Florida. We found that the two higher performing high schools in the study had strong and deliberate structures, programs, and practices that attended to both students' academic and social learning needs, something we call "Personalization for Academic and Social Emotional Learning". Because of the study's inductive focus on effectiveness, we follow our findings with a discussion of theories and prior research that substantiate the importance of schools' attention to the connection between students' academic and social emotional learning needs in high schools.