Finding the key to success for high school students has long been the goal for both school personnel and parents. This study examined the impact of four-year participation in music and/or athletics activities in South Dakota public high schools on student GPA and ACT scores. The data in this study were collected from five Class A high schools located strategically throughout South Dakota. Transcripts representing the classes of 2003-2007 were gathered and separated into categories of four-year musician, four-year athlete, four-year both, and non-four-year participants. These groups were then divided into sub-groups of males and females. Information harvested from the transcripts was limited to gender, ACT, GPA, and level of participation. Descriptive statistics were computed to identify the characteristics of each group. Inferential statistics were computed to respond to each of the four research questions, and independent t tests were performed to determine if there were significant differences in the groups based on their level of participation, non-participation, or gender. This study found that students who participated in four years of music, athletics, or both had higher GPA and ACT scores than their non-four-year participant peers. Four-year music students achieved a significantly higher mean GPA score (M = 3.28) than the non-four-year participants (M = 2.77), t (1161) = 11.07, p = 0.000. Four-year musician/athletes achieved a significantly higher mean GPA score ( M = 3.47) than the non-four-year participants (M = 2.77), t (1210) = 12.20, p =0.000. Four-year musicians achieved a significantly higher mean ACT score ( M = 22.26), than the non-four-year participants (M = 20.27), t (770) = 12.20, p = 0.000. Four-year athletes achieved a higher mean ACT score (M = 20.62) than the non-four-year participants (M = 20.27), t (863) = 1.32, p = 0.187. Four-year musician/athletes achieved a significantly higher mean ACT score (M = 22.47) than the non-four-year participants (M = 20.27), t (672) = 6.35, p = 0.000. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]