At that historic moment of the founding of Vidyalankara University in 1959, the subject of philosophy became one of the major fields and the Faculty of Arts was one of the five disciplines comprising the department of Philosophy. The Headship of the Department held by Ven. Prof. Moratuwe Sasanaratana Thero was the first head of the Department at that period. He was one of the renowned Buddhist scholars in Sri Lanka. 

The Ven. Prof. Moratuwe Sasanaratana Thero was an eminent scholar of Mahayana and Medieval philosophy. He was well-versed in Eastern philosophy. The Department of Philosophy at the University of Kelaniya appears to have undergone three distinct historical eras. That is, the first period, from the Vidyalankara Pirivena era to the establishment of the 1959 Vidyalankara University. The second period, spanning from 1959 to 1977, marked the transition from Vidyalankara Pirivena to Vidyalankara University. The Retirement of Prof. Moratuwe Sasanaratana Thero, Prof. S. G. M. Weerasinghe's appointment as the Head of the Department, and the abolition of the Tamil-medium degree were significant events that occurred in the Department of Philosophy during this period.

Prof. S.G. M. Weerasinghe, the Chair, introduced the Philosophy of Law, making a significant contribution to the field. He also contributed to establishing knowledge in the area of historical Buddhist Legal systems in Sri Lanka, based on Buddhist Legal Philosophy. The year 1977 to 2000 is the third historical period, and during this period, many young lecturers with new ideas joined the Department of Philosophy. Professor Daya Edirisinghe obtained his Master’s degree in Far Eastern Philosophy from Donguk University in the Republic of Korea. Prof. V.G. Kulasena obtained his Doctor of Philosophy Degree in Greece and specialised in Wittgenstein’s Philosophy and Analytical Philosophy. Dr K. Piyasiri specialised in the field of Buddhist Political Philosophy and obtained a Doctor of Philosophy Degree at the National University of Australia. Prof. Jayantha Seneviratne's field of study encompassed Marxism and modern political philosophical traditions, including Peace Studies, Gender Studies, and Non-violence. He later received the educational training in peace and conflict resolution at Uppsala University in Sweden. Prof. Jayantha Seneviratne pioneered the establishment of the Peace and Conflict Resolution Degree in the Department of Philosophy, also known as a pioneer in establishing peace education in Sri Lanka. Dr. Pushpa Rodrigo, who did his Doctor of Philosophy Degree in the field related to Essentialism, Alienation and Aesthetics. Senior Professor Kandegoda Wimaladhamma Thero specialised in the fields of Eastern and Western ethics. As a young monk, he obtained his Doctor of Philosophy Degree in Greece, becoming the first Sri Lankan Buddhist Reverend to hold a PhD in the Greek language. The above-mentioned senior professors and professors, along with the Doctors, made a great effort in the development and advancement of the Department of Philosophy. They can also be considered as the pioneers of young Lecturers who serve in the Department in present.  Prof. S. G. M. Weerasinghe, Senior Prof. (Emeritus) Daya Edirisinghe, Dr K. Piyasiri, Senior Prof. Kulasena Vidanagamage, Prof. Jayantha Seneviratne, Dr Pushpa Rodrigo, and Senior Prof. (Ven) Kandegoda Wimaladhamma Thero represented the third generation of the Department of Philosophy, and all of them held the headship accordingly.  During the fourth period of the Department of Philosophy, Prof. Gamini Hapuarachchi, Dr K.A.T. Dharaneeta  and Senior Lecturer (Mrs.) D.D.R. De Silva holds the headship and is currently a Senior Lecturer Dr. Manoji Harischandra holds the headship of the Department of Philosophy, University of Kelaniya. The distinctive feature of this period is that the third and fourth generations are successfully engaged in their academic activities, contributing to the development of the discipline and the Department. 

The Department of Philosophy offers degrees in three areas: Philosophy, Psychology, and Peace and Conflict Resolution. Currently, the Department of Philosophy offers degrees in both Sinhala and English Medium. However, in 2003, the Department introduced the Bachelor of Arts Degree in Psychology, and in 2007, the Honours Degree in Psychology was introduced. It currently provides degrees in both Sinhala and English Medium.  The Bachelor of Arts Degree in Peace and Conflict Resolution was introduced in 2007 and was later transformed into an Honours Degree in 2018 as a fully English medium Degree course. Therefore, the Department of Philosophy can be identified as one of the larger departments in the University with a higher number of Undergraduates. The Department of Philosophy also offers a Master of Arts (MA) Degree, a Master of Social Science (MSc) Degree, a Master of Philosophy (MPhil) Degree and a Doctor of Philosophy (PhD) Degree in Philosophy. Additionally, the Master of Philosophy (MPhil) Degree and the Doctor of Philosophy (PhD) Degree are available in Psychology and Peace and Conflict Resolution for qualified scholars.