Singh's reign as Maharaja of the princely state of Patiala, in British India, lasted from 1900 to 1938.

Singh was sent to the princely state of Dholpur, supposedly because of threats to his life due to intrigues in the Patiala court.

Singh was well known for the construction of buildings with bold architectural designs in Patiala, including the Shri Kali Devi Temple.

Other buildings he constructed include Chail View Palace in the summer retreat of Kandaghat, Chail Palace and Oak Over and Cedar Lodge in Shimla, which are now the residence of the Chief Minister of Himachal Pradesh and the Punjab State Guest House, respectively.

[2] Most of the buildings of the Chail Military School, in Himachal Pradesh, were donated by Singh to the Government of India.

[17] He was selected as the captain of India on its first Test tour of England in 1932, but dropped out for reasons of health two weeks before departure and Natwarsinhji Bhavsinhji, the Maharaja of Porbandar, took over.

Singh was a co-founder of the Board of Control for Cricket in India (BCCI), the national sports administration body for cricket in India, and the donated the Ranji Trophy in honour of Kumar Shri Ranjitsinhji, Jam Sahib of Nawanagar.

[6] He was noted for collecting various items, including cars, jewels, medals, paintings, watches, wines, and spending sprees in Europe.

[20] One of his wives, Maharani Bakhtawar Kaur, presented Queen Mary of the United Kingdom with a necklace on behalf of the Ladies of India during the Delhi Durbar of 1911.