Self-discipline pervasively impacts most aspects of human life. It also promotes numerous human behaviors with positive psychological outcomes. Two studies were conducted within the scope of this research. The aim of the first study was to develop and test the psychometric properties of the self-discipline scale (SDS) for adults. Validity and reliability analyses were conducted on two different samples attending different universities in Turkey. As a result of the analyses, a valid and reliable scale was developed consisting of the two-dimensional construct and 13 items. The aim of the second study was to test the sequential mediating roles of grit and life-satisfaction in the relationship between self-discipline and peace among college students. The results revealed that self-discipline is positively related to grit, life-satisfaction, and peace. Path analysis showed that the sequential mediating effect is significant for grit and life satisfaction on the relationship between self-discipline and peace. Overall, these results demonstrated that self-discipline makes a significant contribution to a peaceful life, also grit and life-satisfaction have a remarkable role in this contribution.