Globally, the degradation of natural resources and its severe environmental effects is growing. The world is united to work for the environment’s safety and natural resources. Consumers are more conscious of utilizing those products that are harmful to the environment, and organizations are taking the competitive edge of consumer consciousness by providing environment-friendly products. However, it is also essential for organizations to realize that a green and sustainable environment changes the consumption pattern of societies and introduces other factors that can lead to green purchase intention. Besides, to make a consumer green brand evangelist, it is crucial to understand the necessary factors for environmental protection. Therefore, to fill this literature gap, the study aims to examine the effects of green conscientiousness (GC), green motivation (GM), green altruism (GA), and green attitudinal purchase intention (GPI) on green brand evangelism (GBE). The study data of 276 green customers were gathered and analyzed using partial least square structural equation modeling (PLS-SEM). The theory of reasoned action and purposeful work behavior were applied to describe a clear analytical basis for the research model. The study findings reinforce new evidence that green conscientiousness directly affects green motivation and green attitudinal purchase intention. In the focused group, respondents were active green buyers with experience purchasing green products. Our analysis concludes that green motivation significantly mediates green conscientiousness and green attitudinal purchase intention. Besides, green motivation and brand evangelism are significantly mediated by green attitudinal purchase intention. Finally, green altruism significantly moderates the impact of green motivation on green attitudinal purchase intention. The developing country's government and management should invest in evangelists to disseminate the green note to delicate environmental sustainability. Future studies may investigate a composite model that assesses the impact of environmental awareness on brand evangelism, with green purchasing intentions considering a mediating variable.