Marlene started out doing bit parts until she was cast in heavy supporting roles such as the black sheep sister of Paraluman in Anino ni Bathala in 1958, where she won her first the Filipino Academy of Movie Arts and Sciences (FAMAS) Award.
After Sampaguita Pictures declined in the 1960s, she became a freelance actress, giving her more freedom to choose more challenging dramatic roles and winning awards in the process.
Born to a Spanish-Irish father and a Spanish mother, Marlene graduated from Saint Scholastica's College in León Guinto Street, Malate, Manila.
In the beginning, she was entirely a stranger to Tagalog, then the main language used for mainstream Filipino movies because Marlene only spoke English at school and Spanish at home.
Nevertheless, with the help of Rosa Mía and her sacrifices from attending social functions while memorizing her Tagalog lines in between filming sessions, she was able to ace her acting career.