Although smartphone ownership among minors has become an important social phenomenon, its impact on children’s and adolescents’ well-being, as well as the mechanisms by which this might take place are not yet sufficiently well-established. To date, no research has examined the effect of smartphone ownership on the well-being of minors through the consumption of influencer-generated content, nor has it explored the effectiveness of the main prevention strategies employed by parents in this context. To fill those gaps, 800 Spanish minors (50% female) aged from 8 to 16 years old (M = 12.33, SD = 2.38) participated in a correlational study in which the ownership of electronic devices, the consumption of influencer generated content, the parasocial relationship with the influencer, and the most common parental mediation strategies were considered. The results showed a positive association between electronic device ownership and psychological discomfort, problematic usage, and imitation of dangerous behaviors. This association was mediated by the consumption of influencer-generated content and the parasocial relationship established by the minor with the influencer. Regarding preventive strategies, only active mediation was inversely related to poorer well-being indicators, however this positive effect significantly decreased when a smartphone or a similar electronic device was owned by the minor (vs. no owned). These findings contribute to the understanding of how smartphone ownership can affect the well-being of children, emphasizing the need for thoughtful consideration when deciding whether to provide smartphones to minors.