Which medal is given for exceptionally meritorious service in a high-responsibility role within the Navy or Marine Corps?

The Distinguished Service Medal is awarded for exceptionally meritorious service in a high-responsibility role, specifically recognizing leaders or individuals who have made significant contributions to the Navy or Marine Corps. This medal signifies not only outstanding performance in duty but also highlights leadership at levels of high responsibility, where the individual's actions have had a considerable impact on the effectiveness of military operations and the mission success of their unit.

In contrast, the Bronze Star Medal is awarded for heroic or meritorious achievement, while the Silver Star Medal recognizes gallantry in action against an enemy. The Purple Heart Medal is distinctly for those wounded or killed in action and does not pertain to service or achievement in a leadership or high-responsibility capacity. Thus, the Distinguished Service Medal is appropriately aligned with the criteria described in the question.