The contemporary school environment in England has been identified as stressful for both staff and pupils. School-based interventions aimed at improving well-being and mental health have shown mixed results. The Principle Based Model (PBM) of Mind, Consciousness, and Thought is an untried intervention in English schools and as a working model there is a paucity of research into its potential. The aim of this mixed-methods pilot study was to investigate the effectiveness of the PBM as a means of increasing the psychological well-being of staff and pupils. The study was a 16-week pre, post, and follow-up study using the Friedman Well-Being Scale (FWBS) as a measure of psychological well-being, and analyzed using matched sample t tests and repeated measures ANOVA. The study was carried out in a high school in the east of England with 10 staff and nine pupils. The staff and pupils involved received the PBM as a psychoeducational program. During the follow-up period, six members of staff and one pupil were interviewed and the transcripts analyzed using Thematic Analysis. The pre to post total FWBS scores showed an increase in psychological well-being for both staff and pupils but only the change for pupils was statistically significant. Post to follow-up total FWBS scores for both staff and pupils showed no significant change. This study provides some initial evidence to suggest that the PBM may be a useful tool for schools to utilize in attempting to increase psychological well-being.