The king continued the dark path of the leaders before him, doing evil in the eyes of God. He fully embraced the negative legacy left behind by Jeroboam son of Nebat, refusing to step away from it.
The commentators explain that this was not merely a passive continuation of past mistakes. Rather, the king made a deliberate, personal choice to participate in the very sins that caused the Israelites to stumble. He completely attached himself to this destructive way of life, walking willingly in the footsteps of those who led the nation astray.