The Indian Army faced fundamental changes to its identity in the first half of the twentieth century, from who served in its ranks to how they were recruited to who ended up commanding its formations. Unlike many other armies of the same era, it also faced challenging operations across the "spectrum of conflict," from internal security operations to high-end conventional war against peer enemies. Changes in recruitment, “Indianization” of the officer corps, and the ability of the army to adapt to the spectrum of conflict came to define a culture in the Indian Army that was distinct from that of its cousin, the British Army, or of other Dominion Forces. Indian Army culture rested on the firm foundation of its history and ethos, but it was also adaptable enough to deal with the changing environment that occurred outside its domains. The Indian Army faced significant challenges and experienced setbacks; however, during the Second World War, the army reformed and performed at the highest levels of professionalism, especially in 1944 and 1945. Its performance in that conflict was the high-water mark of the largest all-volunteer army in history.

The American Civil War presented an exceptional state of affairs in modern warfare, because strong personalities could embed their own command philosophies into field armies, due to the miniscule size of the prior US military establishment. The effectiveness of the Union Army of the Tennessee stemmed in large part from the strong influence of Ulysses S. Grant, who as early as the fall of 1861 imbued in the organization an aggressive mind-set. However, Grant’s command culture went beyond simple aggressiveness – it included an emphasis on suppressing internal rivalries among sometimes prideful officers for the sake of winning victories. In the winter of 1861 and the spring of 1862, the Army of the Tennessee was organized and consolidated into a single force, and, despite deficits in trained personnel as compared to other Union field armies, Grant established important precedents for both his soldiers and officers that would resonate even after his departure to the east. The capture of Vicksburg the following summer represented the culminating triumph of that army, cementing the self-confident force that would later capture Atlanta and win the war in the western theater.