Background: This study presents the development of a supplementary questionnaire assessing lifestyle behaviors, psychological well‐being, and contextual factors, designed to complement the World Mental Health International College Student (WMH‐ICS) survey, within the Italian Health Mode On project. 

Methods: A preliminary questionnaire, based on a literature review and composed of brief standardized measures across 15 sections, was drafted. Its validation was conducted through a two‐round electronic Delphi process involving 17 experts from Italian universities and research institutes. In the first round, the experts rated the relevance of each section and domain and suggested item revisions or additions. Feedback was synthesized and presented in the second round, during which the experts re‐rated their agreement with all proposed modifications.

Results: All sections proposed in the preliminary version were retained. Experts provided 115 item‐modification proposals and 10 suggestions for new sections or domains; 35 modifications (30.4%) and 3 additions (30%) were accepted. The final instrument comprises 18 sections and 64 items covering anthropometry, socio‐economic status, housing, commuting, physical activity, diet, sleep, nicotine product use, social media, gaming, gambling, loneliness, hopelessness, life satisfaction, academic stress, student services, discrimination, and general well‐being. 

Conclusions: A rapid e‐Delphi process produced a concise, expert‐validated supplement expanding the WMH‐ICS survey's capacity to inform health promotion and prevention interventions.