MTV Shuga is an edutainment campaign designed to equip young people with knowledge, motivation, and informed choices to protect themselves from HIV infection. From 2019 to 2020, a total of 10 episodes of a new dramatic series, MTV Shuga "Down South 2" (DS2), were broadcast via television and the internet, alongside complementary media activities. This study aims to investigate whether the intensity of DS2 exposure was linked with positive HIV prevention outcomes in a setting with high HIV prevalence and relatively low levels of HIV testing. We analyzed data from a web-based survey of participants aged 15 to 24 years in South Africa in 2020. The survey was promoted via social media platforms of schools, universities, and communities in Eastern Cape, South Africa. The primary exposure of interest was the intensity of exposure to DS2, measured by the number of episodes of DS2 watched on the television or the internet or listened to on the radio (out of 10 episodes). Individuals who had not watched or listened to any DS2 episode were classified according to other MTV Shuga content that they had accessed. We estimated associations between the intensity of DS2 exposure and HIV-related outcomes, including knowledge of HIV status, awareness of HIV self-testing (HIVST) and pre-exposure prophylaxis (PrEP), uptake of HIVST, and demand for HIVST and PrEP, adjusting for potential confounders using multivariable logistic regression. Among the 3431 survey participants, 827 (24.1%) were exposed to DS2. Specifically, 18.1% (622/3431) watched or listened to only 1 DS2 episode, and 2.4% (82/3431), 1.7% (58/3431), and 1.8% (62/3431) watched or listened to 2 to 4, 5 to 7, and 8 to 10 DS2 episodes, respectively. Increasing the exposure to DS2 was associated with improvements in most outcomes. Exposure to multiple episodes (eg, 2-4, 5-7, and 8-10) was associated with successively higher odds of knowing one's HIV status, awareness of PrEP and HIVST, and uptake of HIVST compared with no MTV Shuga exposure, albeit with statistical uncertainty around some estimates. The interest in using HIVST or PrEP was high overall (>80%), with no measurable differences by DS2 intensity. We found evidence consistent with a dose-response relationship between MTV Shuga DS2 exposure and outcomes, including knowledge of HIV status, awareness and uptake of HIVST, and awareness of PrEP among young people in Eastern Cape. This indicates that greater engagement with a youth-focused edutainment campaign can improve HIV testing and prevention options in a setting and population with high need. However, only a few participants accessed multiple DS2 episodes despite its availability on multiple media platforms. We conclude that there is potential to benefit more young people by increasing access to and interest in the show.