Ajantha Ranasinghe was born on 30 May 1940^[5] in Thalammahara, a small village in the Kurunegala district as the second of the family with five siblings. His father was a doctor and mother was a teacher as well as a postmaster. He had one elder sister, two younger sisters and a younger brother. After obtaining his primary education at the Pannala Government School, he moved to Colombo and resumed his studies at St. John's College, Nugegoda.^[6] He left after completing the GCE Ordinary Level Exams.^[7]

Ranasinghe was married to Sarojini Weeratunge, the daughter of late singer Kokiladevi Weeratunga.^[2] The couple had two children: Saranga and Devalochana.

Ranasinghe's uncle Asoka Pieris was a well known dramatist, and he came under his influence and through that got to showcase his talent over the airwaves.^[2] At a very young age, Ranasinghe wrote Buddhist songs to the Lama Mandapaya, a program on Radio Ceylon hosted by Karunaratne Abeysekera.^[4] He participated in another program, Radio Magazine, organised by the filmmaker K. A. W. Perera. His first published work, Thivanka Rekha, a poetry collection, came out in 1964.^[8]

He wrote poetry and short stories for the children's pages of Silumina and Peramuna. His poetry was frequently published in Silumina, Vanitha Viththi, and Lankadeepa.^[9] Eventually he was selected as a staff reporter at Dinamina.^[2] He would graduate from and to the posts of Sub Editor, Local News Editor, Additional Chief Sub Editor, Chief Sub Editor, Features Editor, and Chief Editor of Navayugaya.^[10]

After three decades in journalism, Ranasinghe began writing lyrics for popular singers.^[4] His verses became highly popular among the public.^[9] Award after award followed, from the Sarasaviya, OCIC, State Literary, Raigam, Sumathi, and Kumaratunga Munidasa ceremonies.^[6] In addition to being a lyricist, Ranasinghe was also a B Grade Radio Ceylon singer.^[9][2]

• Awarded a doctorate degree by the International Open University, New Delhi in 1995.^[2]
• 25 years as an Editor at Lake House^[11]
• Provincial News Editor and Local News Editor at Dinamina^[11]
• Features Editor of Janatha
• Editor in Chief of Nawayugaya
• Consultant at the Sri Lanka Broadcasting Corporation (SLBC)^[4]
• President's Award for Best Song Writer of the Year on three occasions^[6]
• Lifetime Achievement Award in Journalism Awards for Excellence Programme, organised by the Editor's Guild of Sri Lanka – 2014
• A song festival Ajantha Geethavalokana was held at the Sri Lanka Foundation Institute at Independent Square on 9 May 2002^[12]
• A collection of his songs released in 2002 in a new cassette and CD titled Kalpana Vijithaya^[13]
• A second CD collection released in 2013 titled Ran Kenden^[14]

Ranasinghe died at the Colombo National Hospital on 27 February 2016^[15][16] after a minor accident right opposite his house three days earlier.^[17] His remains were kept at No. 11/4, Ranasinghe Mawatha, Hiripitiya, Pannipitiya at his son's residence.^[9] The funeral was held on 29 February 2016 at the Borella Cemetery.^[18]

• Landuni Mata Varam Natha (1975)^[2]
• Vinkal Bass (1978)^[2]
• Kristhuni Karunakara Manawa (1995)^[2]
• Sihina Kumara Saha Othamo (2009)^[19]
• Thunpath Rata^[20]
• Thiwanka Rekha^[21]
• Janakanthayinge Manakantha Katha^[2]

Dr. Ranasinghe contributed over 300 lyrics to Sinhala films since 1976 with his debut, Wasana.^[1][2]

Ajantha Ranasinghe wrote more than 400 lyrics for singers across several generations.^[22][23]

• Ajantha Ranasinghe at IMDb
• Funeral of Late Ajantha Ranasinghe
• Filmography as a lyricist
• President Wishes Songwriter Dr Ajantha Ranasinghe
• Popular Lyrics Ajantha Ranasinghe shows
• For Ajantha Ranasinghe
• අජන්තා ගැන තවත් නොකී කතා
• වසර 56කට පෙර කවියට නැඟුණු අජන්තාගේ අප‍‍්‍රකාශිත පේ‍‍්‍රමය