Guided by the question “What is the teaching knowledge developed by Art teachers and educators from a formative activity centered on the use of digital technologies?” we conducted an investigation in the context of a formative activity permeated by digital technologies. The activity involved eight teachers from the early years, focusing on the development of necessary knowledge for teaching music at school. The results point to the development of disciplinary knowledge related to the History of Music and Art, musical theory, musical practice and music teaching mediated by technologies; curricular knowledge related to musical writing (score), musical scale, rhythm, melody and harmony, folk music and the content of musical teaching; teacher education knowledge, particularly aspects related to didactic, that is, strategies and resources to develop music teaching; and experiential knowledge on students’ learning challenges.