The adolescent mental health crisis is compounded by a shortage of mental health services, which mobile health apps may alleviate. We assessed the feasibility and acceptability of the Wysa app (a commercially available app containing cognitive behavioral therapy-based digital modules and an artificial intelligence-based conversational agent) among 13- to 18-year-old adolescents recruited from a primary care clinic in New York City and online from March to June 2022. We assessed adolescent engagement in the Wysa app over a 3-week period. Out of 44 participants, app uptake was 77.3% (34/44). Among those who used the app, participants used the app a median of 9 times (IQR: 5–19). Over 3-quarters ( n = 25) of participants who used the app would recommend the app to others, and 60.6% rated the app 4–5 stars (5 stars maximum rating). Pediatricians may find it a useful tool to recommend in their clinical practice to support adolescent mental health.