The commander I think you are talking about is Ulysses S. Grant
Abraham Lincoln as commander in chief, sent union troops to the South.
Ulysses S. Grant
McDowell
Winfield Scott Henry Halleck Ulysses S. Grant
General Ambrose Burnside
The first commander of the Union troops during the American Civil War was Brigadier General Irvin McDowell. He led the Union forces at the First Battle of Bull Run (also known as First Manassas) in July 1861. McDowell's command faced significant challenges, and after the Union defeat in that battle, he was eventually replaced by General George B. McClellan.
General George G. Meade
General George G. Meade
There were several Union generals in different theaters of war. Scott, Hallack, McClellan, Pope, Burnside, Hooker, Meade, and Grant all served as overall commander of the Union forces as various times.
The Union commander was Ulysses S. Grant
Alexander
The Union commander was Brigadier General Samuel Curtis, the Confederate Comamnder was Major General Earl Van Dorn.