[1] Born to a well to do family in Gonahena, Kadawatha in the Gampaha District, he was the eldest with four younger sisters.
As a student he got quickly involved in the revolutionary that became the Janatha Vimukthi Peramuna (JVP) becoming one of its founding leaders along with Rohana Wijeweera.
Becoming an active member, Jayasinghe adopted the nom de guerre "Loku Athula" and became one of the top four leaders.
He was responsible for armed wing of the group and took command of its carders in the districts of Kegalle and Kurunegala.
He was unsuccessful in holding the area and withdrew to the jungles of Wilpaththu, where he was captured with what of left of his carders which had reduced to 40 from 300.