Owing to the poorer explicit successful performances, the grassroots level inventors in developing countries were not given needed attention and acceptable level recognition. Therefore, the question of why these inventors continuously involved in inventive activities where surroundings are becoming hostile to independent inventing remained unanswered in the literature. The present study aims to fill the said knowledge gap by exploring the demographic, psychological, technical and social causes and consequences of objective and subjective success of grassroots level inventors in Sri Lanka. The study was designed as a correlational research. Out of 640 patent applied grassroots level inventors in Sri Lanka between the year 2000 and 2008, 200 were randomly selected as the sample of the study. The sample represented 31% of the target population, and it has provided the acceptable statistical power 0.80 at 0.05 confidence level. According to the bottom-up path model, income, engagement in inventive activities and external linkages have positive influence on the objective success of grassroots level inventors. On the other hand, grassroots level inventors' marital status, internet usage, life orientation and social capital have significant positive influence on the subjective success of inventors. More importantly, selected inventive life inputs: income, engagement in inventive activities and external linkages as well as the outcomes: objective success, inventive career satisfaction and community connectedness have significant indirect and direct positive influences on subjective success respectively.