During the Great Sioux War of 1876 Crawford was civilian scout with the 5th Cavalry Regiment and war correspondent for the "Omaha Bee" with General George Crook's Yellowstone and Big Horn Expedition. Captain Jack is credited with carrying dispatches on a highly perilous route of 400 miles alone to Fort Fetterman, and he took part in the Horsemeat March of 1876, one of the most grueling marches in American military history. Crawford played a significant role in the Battle of Slim Buttes (1876) and made a daring ride of more than three hundred miles in six days to carry dispatches of the victory to Fort Laramie for the "New York Herald". One of his most famous exploits included delivering a bottle of whiskey to Buffalo Bill Cody, while on campaign. Cody wrote of the incident in "An Autobiography of Buffalo Bill":