John Gill Commentary 2 Kings 21:20

"And he did that which was evil in the sight of Jehovah, as did Manasseh his father." — 2 Kings 21:20 (ASV)

And he did that which was evil in the sight of the Lord
Committed idolatry:

as his father Manasseh did :
he imitated him in that, but not in his repentance and humiliation, (2 Chronicles 33:23) .