[3] He opposed the Khalistani separatists among the NRI Sikhs, and actively campaigned against them through his articles and speeches.

[3] He represented Garhshankar Assembly constituency in Hoshiarpur district as member of Punjab State Legislature for two terms from 1972 to 1980.

[3] On the afternoon of 25 September, Darshan Singh was killed by Sikh militants during the insurgency in Punjab, India.

[6] Within two hours of his death, about a thousand demonstrators gathered at the police station at Mahilpur, and blocked the way to Hoshiarpur.

The people shouted slogans as "Darshan Singh Canadian Amar Rahe" (Long Live Darshan Singh Canadian), "Canadian aman ekta da shahid" (Canadian was a martyr to peace and unity), "Na Hindu Raj na Khalistan, jug jug jive Hindustan" (Neither Hindu Raj nor Khalistan, long live India), "Hindu Sikh noon jo ladaye, oh desh da vairi hai" (he who makes Hindus and Sikhs fight, is an enemy of the nation), "atvad wakhwad murdabad" (down with extremism and secessionism), "Lokan da ekta zindabad" (Long live public unity), "Hindu Sikh ekta zindabad" (Long live Hindu-Sikh unity), and "CPI zindabad" (Long live CPI).