Introduction: Leveraging every interaction between patients and healthcare professionals constitutes an opportunity to foster behavior change. We developed a mobile Screening and Brief Intervention (mSBI) designed to screen for and intervene with multiple health behaviors, based on a personalized feedback. The objectives of the present study were to assess its feasibility during consultations for chronic conditions, collect users’ opinions, and to investigate patients’ behaviors and intention to change. Methods: Research counselors provided the mSBI to patients from 2 departments at University Hospital. Socio-demographic, behavioral, and acceptability data were collected from patients together with feasibility data from counselors’ reporting. Results: A total of 259 participants were analyzed, aged 51 ± 17 years, with a majority of women (53%). The m-SBI averaged 20 min and most patients (92%) could complete the screening with minimal assistance. Medical doctors’ involvement facilitated referral to and uptake of the m-SBI, and limited adverse events. On average, patients adhered to 11 of the 18 guidelines screened. A majority of patients rated the personalized feedback as comprehensible and useful. Nearly half of them intended to change behavior. Conclusions: The m-SBI seems well-accepted and useful, but doctor referral, adapting the screening tool to patients with low health literacy, and app’s ability to send the feedback to patients/doctors are essential for feasibility.