Initially Henderson was named as the parliamentary assistant (PA) for the Ministry of Community and Social Services. In 1986, Henderson took a highly public stance against the Liberal government in its attempt to ban extra-billing by doctors, a practice by which physicians bill patients directly an amount in addition to what is provided by the provincial health plan, and was generally supportive of doctors in their illegal strike that followed. Consequently, he fell into disfavour with the premier David Peterson, and was generally regarded as being on the political right of the Liberal Party.