Answer
The answer is no. Wang Jingwei was a prominent member of the Kuomintang, the party of China's Nationalist Government, and served in several high-ranking positions, but he never formally became the leader of the government. During World War II, Wang led a faction of the Kuomintang that collaborated with the Japanese, but he did not control the Nationalist Government itself, which was led by Chiang Kai-shek.