Zhang was appointed vice-chairman of the commission last December, and he is in charge of climate change issues, investment in fixed assets and rural development.
His predecessor Xie Zhen-hua was recently appointed China's special representative on climate change affairs and will work with Zhang on climate issues until at least December.
The State Council issued a document on Tuesday that said the environment should be protected in a sustainable way alongside efforts to boost economic prosperity.
The document revealed that a lifelong accountability system is to be set up to track officials' performance in the field of environmental protection.
Officials will assume accountability for their decisions if they damage the environment, even after they leave their posts.
"This accountability should not be limited to single projects, but should also apply to the formulation of policy," Zhou said.