Which Confederate general was Lee's second-in-command (First Corps commander) at Gettysburg?

James Longstreet was Lee’s second-in-command and the Confederate First Corps commander at Gettysburg. Robert E. Lee relied on Longstreet as his senior lieutenant, famously calling him his “old war-horse.”

Longstreet commanded the First Corps of the Army of Northern Virginia during the July 1863 campaign. His corps included the divisions of Lafayette McLaws, John Bell Hood, and George Pickett. At Gettysburg, Longstreet supervised major Confederate attacks on July 2 and July 3, including the assault later known as Pickett’s Charge.

He was not simply a battlefield subordinate with a small detachment. As a lieutenant general and corps commander, Longstreet directed several divisions and played a central role in Lee’s operational decisions. He also disagreed with Lee’s preference for attacking the Union position directly, favoring a maneuver around the Union left that might force the Army of the Potomac to abandon its strong defensive ground.

The other options held important commands, but none was Lee’s First Corps commander at Gettysburg: Stuart led cavalry, A. P. Hill commanded the Third Corps, and Ewell commanded the Second Corps.