Which individual is known as the "Grand Old Man of the Marine Corps"?

The title of "Grand Old Man of the Marine Corps" is attributed to Archibald Henderson due to his significant and lasting impact on the Corps during his tenure as the 5th Commandant from 1820 to 1859. Under Henderson's leadership, the Marine Corps underwent substantial growth and modernization. He is credited with establishing many of the organizational systems and traditions that continue to influence the Marine Corps today.

Henderson's advocacy for the Marine Corps and his vision for its future helped elevate the status of the Marines in the military and broader society. His dedication to improving training and enhancing the capabilities of the Corps solidified his legacy, earning him the affectionate title among Marines. His strategic thinking and commitment to the Corps' mission during crucial periods, like the Mexican-American War, further underscored his pivotal role in shaping the Marines.

The other individuals mentioned have made their own important contributions, but none have had the same long-standing influence or recognition as Archibald Henderson in the context of Marine Corps history. Therefore, his storied career and essential role in the development of the Marine Corps are why he is honored with this particular title.