[3] A veteran actress acting for a span of seven decades, she began her career in Sri Lankan cinema with Tissa Liyansooriya's Punchi Baba in 1968.

She has also made a record by winning the Slim Nielsen Peoples' Award for the Most Popular Actress twelve times in a row.

[13] She made her film debut with Tissa Liyansuriya's Punchi Baba (The little Baby) in 1968, followed by Abudasse kale, Dahasak Sithuwili and Adarawanthayo in the same year.

Her career was enhanced by her work alongside Gamini Fonseka who had a long journey in the history of the silver screen in Sri Lanka.

[14] Some of her successful films are Nidhanaya by Lester James Peiris, Siripala Saha Ranmenika by Amaranath Jayathilake, Eya Den Loku Lamayek and Bambaru Ewith by Dharmasena Pathiraja.

Fonseka has been praise for her performance in Manalada Puthe Kiri Dunne, Pitagamkarayo, Kemmura, and Ambu Daruwo teledramas.

In 2024, Malini Fonseka took on an incredible role in the music video for Eya Wasanthaya Nowe (එය වසන්තය නොවේ) by the promising young vocalist Chapa Jayaruk.

Her performance in the video was widely praised, showcasing her superb acting skills and adding another remarkable achievement to her illustrious career.

[18] In January 2008, Sri Lankans living in the United States gathered in large numbers at Los Angeles to honour her, alongside a special dinner hosted by the Consular General of Sri Lanka to the Consulate in Los Angeles, Jaliya Wickramasuriya and his wife, followed by an honouring ceremony where she was awarded with an Appreciative Plaque by the Consulate General.