This king was different. He trusted in the Lord. He must have trusted God for everything because Verse 5 says there was none that came after him or before him that was like him. Verse 6 said that he gave to the Lord and didn't depart from following Him and also kept His commandments. The outcome of his relationship with God and his obedience was that the Lord was with him and prospered him wherever he went. God rewards obedience. He hates disobedience. All God ever wanted was people to love Him and keep His commandments and worship only Him.
Hezekiah was just that kind of king and that's why God prospered him in all he did. If we want to please God, we too must trust Him and follow Him with all our hearts. When we do, we too will know what it's like to live in obedience.