Born at Penshurst, Kent, he was the eldest son of Sir Henry Sidney, and was educated at Christ Church College, Oxford. He was much travelled and highly learned. He was knighted in 1582, and three years later became governor of Flushing in the Netherlands. He married Frances, daughter of Sir Francis Walsingham.
Sir Philip's life ended prematurely when he suffered a fatal wound at the Battle of Zutphen. His great work, Arcadia, was only published after his death.
The most famous story about Sir Philip (intended as an illustration of his noble character) is that, while dying, he gave his water-bottle to another wounded soldier, saying, "Thy need is greater than mine".
The Rye House conspirator, Algernon Sydney, was Sir Philip's great-nephew.