Jamieson, Fausset and Brown on 2 Chronicles 27:2

2. he did that which was right--The general rectitude of his government is described by representing it as conducted on the excellent principles which had guided the early part of his father's reign.

the people did yet corruptly--(See 2Ki 15:35); but the description here is more emphatic, that though Jotham did much to promote the good of his kingdom and aimed at a thorough reformation in religion, the widespread and inveterate wickedness of the people frustrated all his laudable efforts.