This article reports on a 10-year longitudinal study of children’s musical identity, their instrumental practice, and subsequent achievement and motivation for playing music. Before commencing learning on their instrument, participants (N = 157) responded to questions relating to how long they thought they would continue playing their instrument. Once learning commenced, practice was measured using the parents’ estimates each year for the first 3 years of learning, and performance was measured using a standardized test. Ten years later, the participants were asked how long they had sustained music learning along with other questions related to their musical development. Those who expressed both a personal long-term view of playing an instrument before they began instruction, and who sustained high amounts of practice in the first 3 years, demonstrated higher achievement and a longer length of time spent in music learning compared to those with a short-term view and low levels of practice. Results suggest that while practice and self-regulation strategies are important, learners who possess a sense of where their future learning might take them and whose personal identity includes a long-term perspective of themselves as a musicians are better positioned to succeed and sustain with their instrumental learning.