Adolescent girls and young women (AGYW; ages 15–24) in sub-Saharan Africa face many barriers to accessing preventive sexual and reproductive health (SRH) services. We drew upon the strengths of two complementary approaches, human-centered design and behavioral economics, to craft a holistic, highly-tailored, and empathetic intervention to motivate AGYW to seek contraception and HIV self-test kits at community drug shops. To encourage engagement, we embedded “nudge” strategies at different opportunity points (uncovered during our design research) along the care-seeking and service delivery journey.  Our Malkia Klabu intervention is a loyalty program designed to enhance drug shops’ role as SRH providers through which AGYW earned punches for shop purchases redeemable for small prizes; free SRH products could be requested at any time. From our 4-month pilot in Shinyanga, Tanzania, we assess the extent to which different behavioral nudge strategies motivated behaviors as predicted by synthesizing findings from (1) in-depth interviews with AGYW and shopkeepers, (2) shop program records, (3) shop observations, and (4) customer exit surveys. Overall, we find that AGYW and shopkeepers were motivated by many intervention features as intended and consistent with hypothesized mechanisms. We found strong evidence of social norms for helping to spread awareness of Malkia Klabu among peers, prize incentives for drawing AGYW back to shops, and the opt-out default membership gift of an HIV self-test kit for encouraging testing uptake and exploration of contraceptives. Shopkeepers in both arms noted increased community status from distributing HIV self-testing kits (ego). Malkia Klabu shopkeepers experienced increased customer traffic and business revenues (incentives), which reduced shopkeepers’ gatekeeping tendencies and earned them additional recognition as champions of AGYW well-being. Integrating human-centered design and behavioral economics was effective for developing an innovative and effective intervention that simultaneously met the different needs of economic actors in support of public health priorities.