This study aimed to explore the effectiveness of purposeful instruction on listening comprehension (LC), task-specific motivation (TM), and perceived difficulty (PD) through mixed research. Fifty six second-year Korean high school students participated in this study and were assigned to two groups: the purpose group and the non-purpose group. They took 13 LC tests, responded to 13 TM surveys, and checked 13 PD levels over a period of four months. They also participated in written interviews. The results indicated that the purpose group showed greater overall advantages than the non-purpose group in terms of the mean scores of LC tests, the TM levels, and the PD levels. Additionally, the former group showed more positive attitudes toward their tasks with listening purposes in mind, clearly indicating the pedagogical importance and benefits of purposeful teaching and learning. More details are discussed and provided based on the results.