In 1898, Mislan returned to his hometown where he became the director of the Municipal Band. This was an important position, held in high regard by the society of the time. In 1906, he met a young musician by the name of Juan F. Acosta and took him under his wing. The older performer taught Acosta music composition and harmony and, when Mislan moved from San Sebastian to the town of Barceloneta, he recommended that Acosta replace him as the new director of the San Sebastian Municipal Band.
