Scaffolding is widely referenced in educational literature and practice, in literacy education in particular, but often in reductive ways. Scaffolding is key for diverse youth in high-need settings, but few studies examine complexities and tensions of scaffolding in practice. This study asked how, if at all, teachers at a California high school with a mission to prepare urban, low-income, mostly Latina/o youth for academics and college admission enacted scaffolding to help students, many of them English learners, achieve academic goals. Drawing upon school and classroom data collected over a year and a half, including videorecorded observations, interviews, and student work samples, the study used observation instruments and qualitative analyses to answer questions using two teacher cases. Considering scaffolding for whom, teachers supported students they hoped to see achieve but whom they felt needed many supports, given histories of low test scores and some academic failure. In scaffolding for what purpose(s), much attention was devoted to scaffolding basic and intermediate levels of literacy activity, with less evidence of scaffolding disciplinary literacy and higher-order thinking. For scaffolding how, planned scaffolds of sequenced activities dominated, with promising examples of interactional scaffolds. One teacher case illustrates routine support, while the second illustrates scaffolding aligned with core elements of contingency, fading, and transfer of responsibility and with use of sociocultural dimensions of learning. The study highlights promise and tensions in scaffolding learning for Latino/a students in one urban public high school, with implications for teaching youth of color in low-income settings, teaching English learners, and preparing teachers for this work.