
Before entering politics, he served in the Singapore Army, rising to the rank of Brigadier-General. On 5 September 2017, Prime Minister Lee Hsien Loong announced he will nominate Tan as the next Speaker of the Parliament of Singapore. Tan's new role comes following the resignation of Halimah Yacob as Speaker to contest in the Presidential Elections 2017. Tan is also the President of the Singapore National Olympic Council, a position which he has held since 2014.
In 1987, Tan joined the Singapore Armed Forces (SAF). He went on to hold the positions of Commander of the 7th Singapore Infantry Brigade, Commander of the Army's 3rd Division, Assistant Chief of General Staff (Plans) and Chief of the Training and Doctrine Command (TRADOC), and rose to the rank of Brigadier-General. Following the 2004 Indian Ocean earthquake and tsunami, Tan served as the commander of the SAF's Humanitarian Assistance Task Force in Meulaboh, Indonesia. In 2009, Tan served as the Chairman of the Executive Committee for Singapore's National Day Parade. On 25 March 2011, Tan left the SAF in order to stand for Parliament.
On 11 September 2017, Tan relinquished his role as Minister for Social and Family Development and was nominated as the 10th Speaker of Singapore Parliament. Tan was educated at Anglo-Chinese School and Raffles Junior College. In 1988, he was awarded an SAF Overseas Scholarship to study in the United Kingdom, where he completed a BSc (Econ) degree at the London School of Economics and a Master of Arts degree in Defence Studies at King's College London. In 2008, he completed a Master in Public Management degree at the National University of Singapore's Lee Kuan Yew School of Public Policy. Tan is married with two children. He is an avid photographer and enjoys reading, watching movies and football.