Malini started her film career acting opposite Veteran Cinema actor Joe Abeywickrama in 1968 in her debut film "Punchi Baba". Joe Abeywickrama takes the honour in introducing Malini Fonseka to the Sri Lankan silver screen as well.

Malini has co-starred with Tony Ranasinghe, Gamini Fonseka, Wijaya Kumarathunge, Tissa Wijesurendra, Robin Fernando, Wally Nanayakkara, Roy De Silva, Ananda Jayaratne, Milton Jayawardena, Upali Senanayake, Anesly Dias, Hendry Jayasena, Alexander Fernando, Amarasiri Kalansuriya, Ravindra Randeniya, Sanath Gunatileke, N P Jayatissa, Edmond Jayasinghe, Oswald Jayasinghe. Sashi Wijendra, Cletus Mendis, Somi Ratnayake and Lucky Dias.

Malini has also co-starred with legendary Indian actor Sivaji Ganeshan and Pakistani actor Usman Fiersad.

Malini has played the leading female role against WIjaya Kumarathunge in 41 films, which makes him the actor who has co-starred Malini in the most number of films.