How did Ulysses S. Grant become commander of all Union armies?

Ulysses S. Grant rose to command all Union armies primarily due to his consistent battlefield successes and strategic acumen during the American Civil War.21

After securing early victories at Fort Henry and Fort Donelson, Grant demonstrated his ability to execute decisive campaigns, most notably the Vicksburg Campaign, which successfully split the Confederacy along the Mississippi River.21

President Abraham Lincoln recognized Grant’s effectiveness, particularly in contrast to the struggles of Gen. Henry W. Halleck to develop a coherent grand strategy. Consequently, in 1864, Lincoln promoted Grant to the rank of lieutenant general, placing him in command of all Union forces. From this position, Grant implemented a coordinated strategy, directing William Tecumseh Sherman to advance on Atlanta while Grant himself engaged Robert E. Lee in Virginia, ultimately leading to the Union's victory.21