He served in the Punjab Legislative Assembly from 1952 to 1969, holding many portfolios including the Agriculture, Development and Home ministries.

Even though he was never appointed as a Union Minister, he retained deep influence in the party being elected Deputy Leader of the Congress in the Lok Sabha in 1971.

The 1980s were a turbulent time in the history of Punjab marked by an increase in violence and demand for a separate Sikh homeland, Singh remained Chief Minister for three years.

There was a spate of assassinations, the prime among them being the daylight murder of Lala Jagat Narain, Head of the Punjab Kesri group of newspapers of Jalandhar.

This was followed by the assassination of DIG of Punjab Police Jalandhar range Avtar Singh Atwal outside the Golden Temple Complex.