This Bible verse is about Egypt's Pharaoh. Initially it was Pharaoh himself who chose to harden his own heart; five times he refused to let God's people go. Only after these five times it was the Lord who hardened Pharaoh's heart, while He ministered to His people Israel (Exodus 9:12). God knew in advance that Pharaoh would harden his heart, but even so He gave Pharaoh multiple opportunities to make the right choice.
Man's bad choice always precedes the hardening of the heart. Also, God's hardening of Pharaoh's heart did not mean that this was the sole reason that Pharaoh would perish for eternity.