<p>This study investigated Nigerian youth’s engagement with mainstream media political news on Facebook. Also, it investigated the influence of rejection personality trait and loyalty to the mainstream brand on engagement. Drawing on the uses and gratification theory, the researchers surveyed 417 Nigerian youth who are active Facebook users across the six geopolitical zones in Nigeria through convenience and snowballing techniques. Findings established that youth in Nigeria predominantly consumed news from television mainstream media on Facebook, and established that Facebook has evolved as the primary source of encountering political information and news from mainstream media in Nigeria. Also, the study confirmed that Facebook’s algorithmic structure plays a dual role in structuring youth exposure and engagement with mainstream media political news. Firstly, the algorithmic news curation of the digital media enhances the exposure of incidental news encounters of up-to-date and trending political news. Secondly, it strengthens pre-existing beliefs and broadens youth political awareness and knowledge, without deliberate information seeking. Importantly, the study found no significant correlation between rejection sensitivity and loyalty to a news media brand and engagement. The study, therefore, recommended the need for mainstream media organisations to adopt digital platform content strategies in their news production and dissemination efforts by optimising news for algorithmic visibility and engagement. This research demonstrated how social media enhances easy and continuous access to political information among youth, thereby contributing to Sustainable Development Goal (SDG) 16 on equitable and inclusive information access in democracy.</p>