He was recognised as the Best Cadet of the Officers' Training School, Belgium, the war-time equivalent of the Sword of Honour.

He was commissioned into Jat Regiment and after India gained independence, moved to the 5th Gorkha Rifles (Frontier Force).

His son Yashvardhan Kumar Sinha, a former diplomat, is serving as present Chief Information Commissioner.

He was involved as a junior staff officer in organizing the massive airlift from Delhi to Srinagar in October 1947.

In 1949, he was appointed Secretary of the Indian delegation on the delineation of the Cease Fire Line in Kashmir at a meeting convened by the United Nations.

He led the Indian delegation to Italy in 1972 for a conference on the application of human rights to warfare.

[9][10] Vaidya was in charge when Operation Blue Star (the June 1984 storming of the Golden Temple) took place.

In 2003, when he took over as Governor of Jammu and Kashmir, on average, ten people were killed every day and the annual arrival of tourists was a mere 28,000.

With an improved security situation, tourist arrivals increased from 28,000 a year to 600,000 by 2008, when he relinquished the appointment of Governor.

He inaugurated seminars and conferences on Kashmiriyat at Srinagar, with scholars from Pakistan and several Central Asian states.