This paper examines mindfulness as a costless cognitive asset in reducing stress and improving subjective well-being and psychological well-being among Malaysian bottom-forty-percent and middle-forty-percent income earners, known as B40 and M40, respectively. The participants recruited for this experimental study were divided into intervention and control groups and completed pre- and post-assessment questionnaires. The leveraging on digital technologies during pandemic times from May to June 2021 enabled participants in the intervention group (n = 95) to undergo four weekly online mindfulness intervention sessions through Google Meet and completed daily home mindfulness practices using the mobile application for mindfulness: the MindFi version 3.8.0 mobile app. Based on the Wilcoxon signed-rank test, the intervention group's mindfulness and well-being levels increased significantly after four weeks. This outcome contrasted to those in the control group (n = 31), who exhibited lower mindfulness and well-being levels. The PLS-SEM structural model consists of mindfulness as an independent variable, subjective and psychological well-being as dependent variables, and perceived stress and financial desire discrepancies as the mediators. This model has a goodness-of-fit of 0.076, proving that it is a fit and strong model. There is a positive relationship between mindfulness and subjective well-being (β = 0.162, p-value < 0.01). This model supports the mediation effect of perceived stress between mindfulness and subjective well-being variables (β = 0.152, p-value < 0.05). The overall structural model implies that the effectiveness of mindfulness intervention training not only enhanced bottom- and middle-income earners' well-being but also lowered the perceived stress level that, henceforth, brought the mind and body together in the present moment.