He was previously the Opposition Leader in the House of Representatives of Thailand from 23 December 2021 to 20 March 2023.

He graduated with a bachelor's degree in medicine from the Faculty of Medicine Siriraj Hospital Mahidol University in 1986 and a master's degree in Public Administration from the National Institute of Development Administration in 1999.

[citation needed] Cholnan was a physician at Wiang Sa Hospital, Wiang Sa District, Nan Province, and used to be the Director of Somdej Phra Yuparat Pua Hospital, Pua District, Nan Province between 1995 and 2000.

In 2004, he was appointed as the Secretary to Deputy Minister of Public Health and in 2005 as the Secretary to Professor Suchai Charoenratanakul, the Minister of Public Health under the Thaksin Shinawatra premiership.

Under Yingluck Shinawatra's government, Srikaew was appointed Deputy Minister of Public Health on 27 October 2012, until June 2013.