Involuntary celibates (Incels) are predominantly young males who grapple with a lack of sexual relations and participate in online forums characterized by misogyny, fatalism, and suicidal ideation. This study utilizes a computational social science approach to profile contributors to three prominent Incel forums: r/Braincels, r/Incels, and r/IncelsWithoutHate. Through mixed-method analyses, we examine the characteristics of Incel forum users and identify prevalent themes in their expressions of suicidality. Firstly, employing network analysis and the Walktrap Community Detection Algorithm, we examine the main concerns and interests of 116,266 Incel forum users (identified by their forum visits), exploring whether their initial engagement with suicide-related forums and forums associated with other difficulties preceded or followed their initial participation in Incel communities. Our findings align with media portrayals, emphasizing that Incels are predominantly young males struggling with romantic and sexual disconnection, loneliness, body image concerns, depression, and suicidal ideation. Additionally, many engage with other controversial and politically charged forums, such as r/theDonald. Chronological analysis of their posting patterns suggests a simultaneous engagement with mental health-related content (such as r/depression) and their initial participation in Incel forums. Secondly, we analyze the underlying reasons behind expressions of suicidality among Incels. Employing thematic analysis, we detected prevalent themes in posts made by Incel forum users in the r/SuicideWatch forum. Our findings identify seven overarching themes associated with feelings of suicidality among Incels: social isolation, frustration with celibacy, appearance insecurities, mental health issues, familial and educational issues, and a pervasive sense of worthlessness. These findings may have significant implications for intervention strategies. We advocate for exploring proactive measures that harness innovative technologies, intervening before individuals fully embrace the Incel ideology and become deeply entrenched in communities that propagate a culture of hopelessness. In summary, by analysing Incel forum users’ other internet behaviours over time, we identified several inter-related factors associated with involuntary celibacy. This suggests the need for proactive interventions to mitigate the adverse effects of these factors on individuals and society at large.