Chandrika Bandaranaike returned to Sri Lanka and was active in women's issues. In 1978 she married a very popular film star, Vijaya Kumaratunga, who was also active in politics. He went on to found the Sri Lanka People's Party with her as Vice-President.

One of the party's key goals was to find a peaceful solution to the Tamil problem. The Tamils are a minority community in Sri Lanka who had formed a rebel movement in the early 1970s and some Tamils had joined together to form the Tamil Tigers or LTTE with the aim of creating an independent Tamil state. The LTTE were responsible for repeated attacks and the Kumaratungas were trying to negotiate with the rebels. But in February 1988 Vijaya was assassinated by unknown attackers in front of his wife at their home. After her husband's funeral in a ceremony attended by half a million mourners, Chandrika Bandaranaike Kumaratunga was chosen to lead the new coalition in his place. Following a number of death threats from extremists, she left Sri Lanka for England where she stayed for three years.