At first he rejected the 1968 occupation of Czechoslovakia by Warsaw Pact forces, but later became a prominent figure in Gustáv Husák's regime.

He resigned as prime minister on 12 October 1988 due to conflicts with Communist Party chairman Miloš Jakeš, a hard-liner.

Following the Velvet Revolution of 1989, Štrougal decided to retire from politics; he was ultimately expelled from the party in February 1990.

In 2022, Štrougal was again put on trial, along with former Interior Minister Vratislav Vajnar [cs], for ordering the killing of citizens trying to cross the border into the west.

However, experts from the psychiatric hospital where he was being treated said he was suffering from mild dementia and could not comprehend the court proceedings.