Emotion understanding is an important competency that children begin to develop during the first years of life and serves as an essential building block for lifelong learning. Emotion understanding is linked to developmental outcomes including academic, cognitive, and social-emotional skills. Not surprisingly, efficacious interventions to promote children's social emotional skills have been developed. Scale-up of these interventions is challenging because they are time and resource intensive. Brief, fully automated interventions are promising alternatives to overcome implementation barriers. Mission FEEL! is a two-session, fully automated intervention grounded in cognitive-behavioral theory aimed at promoting emotion understanding among preschoolers. This proof-of-concept study examined the acceptability and feasibility of Mission FEEL!. We recruited 52 preschool children and their parents/guardians across Florida. Participants completed four virtual study visits: a baseline emotion understanding assessment, two intervention sessions, and a one-month follow-up emotion understanding assessment. We established a priori benchmarks to determine feasibility, acceptability, and clinical meaningfulness. The results indicated that Mission FEEL! is both feasible and acceptable. All outcomes, except two that were in the acceptable range, met the benchmarks for good or excellent. The clinical meaningfulness of the intervention was supported by parental perceptions of the program's influence on emotion-related parent-child interactions, perceived value of the program in children's daily lives, and observed difference in emotion understanding scores between baseline and follow-up. The ease of scale-up, low cost, and potential practical implications also contributed to the clinical meaningfulness. Findings from this proof-of-concept study suggest that Mission FEEL! merits advancing to the next phase of intervention development testing.