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 organized training camps and began training members in martial arts. 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. He was wounded in the final encounter with the
Ceylon Army and was sent to Colombo for medical treatment. He was the 6th accused in the
Criminal Justice Commission prosecution of the perpetrators of the insurrection. He turned
crown witness along with W.T. Karunarathne, becoming a witness for the prosecution against the accused and gained a pardon in 1975. ==Political career==