This book LNCS15828 constitutes the refereed proceedings of the 19th International Joint Conference on Theoretical Computer Science-Frontier of Algorithmic Wisdom (IJTCS-FAW 2025), consisting of the 19th International Conference on Frontier of Algorithmic Wisdom (FAW) and the 6th International Joint Conference on Theoretical Computer Science (IJTCS), held in Paris, France, during June 30-July 2, 2025. The 28 full papers and 2 short papers were carefully reviewed and selected from 63 submissions. The proceedings focuses on Frontiers of Algorithmic Wisdom; Block-chain, Distributed Computing, Multi-Agents; Game Theory, Algorithmic Game Theory, Machine Learning, Electronic Commerce. .