Introduction We investigated the experience of individuals diagnosed with type 2 diabetes mellitus (T2DM) who participated in an intervention in which the key elements were the provision of a smartphone and self-monitoring software. The interviews focused on use of a smartphone and the effects on motivation for health behavior change. Methods This was a qualitative evaluation of participants in a larger T2DM self-management randomized controlled trial (RCT) conducted at the Black Creek Community Health Centre (BCCHC) in Toronto, Canada (ClinicalTrials.gov Identifier: NCT02036892). The study is based on semi-structured interviews ( n = 11) that were audio taped and analyzed with a thematic analytic approach. The RCT compared the effectiveness of six months of smartphone-based self-monitoring and health coaching with a control group who received health coaching without internet or smartphone-based assistance. Results Qualitative data analyses resulted in derivation of four major themes that describe participant experience: (a) ‘smartphone and software’, describes smartphone use in relation to health behavior change; (b) ‘health coach’ describes how client/health coach relationships were assisted by smartphone use; (c) ‘overall experience’ describes perceptions of the overall intervention; and (d) ‘frustrations in managing chronic conditions’ describes difficulties with the complexities of T2DM management from a patient perspective. Discussion Findings suggest that interventions with T2DM assisted by smartphone software and health coaches actively engage individuals in improved hemoglobin A1c (HbA1c) control.