Cohen began working as an actress during the late 1960s, firstly in adaptation of literary works such as Alexandre Dumas Pere's Count of Monte Cristo or Wolfgang Goethe's Doctor Faust, both in 1969. She also appeared in episodes of TV series Estudio 1.
She then began working in the Spanish horror cinema industry in 1970, with Cuadecuc, vampir (where she was uncredited) and The Nights of Dracula, both acting as a vampire woman. She also appeared in comedies such as Amo mi cama rica, Spaniards in Paris or Pierna creciente, falda menguante, all of them in 1970. In fact, she appeared in no less than 12 movies only in 1970, always in minor roles.
It was in Pierna creciente, falda menguante that she first worked alongside actor and director Don Fernando Fernán-Gómez, with whom she would work again many times during her career, and with whom she would begin a long relationship.
During the 1970s, she continued with Spanish comedies and low-budget horror flicks, anyhow with little international aims except for co-productions with Italy or France. She also worked again with Fernán-Gómez in cinema (Bruja, más que bruja, 1976), TV movies (Juan soldado, 1973) and TV series (El Pícaro, 1974, where "Emmanuela Beltrán" was a writer and he was the star). Only occasionally she had a chance to return to the classics (Luis Vélez de Guevara's El Diablo Cojuelo, 1971). The end of Spanish censorship during the late 1970s, after dictator Francisco Franco's death, gave rise to a new kind of cinema of "destape" ("uncovering"), a trend where Cohen also worked at.
As a secondary actress, Cohen usually had the chance to work in many productions during one year. For instance, on 1978, she worked in three movies, and it was a low ratio for her.
However, on 1979, Cohen began working in the Spanish version of Sesame Street. Barrio Sésamo featured as main stars two muppets, snail Perezgil and La Gallina Caponata. Cohen would portray Caponata, a presumed chicken who was more than casually similar to Big Bird. Caponata was a shy, child-like muppet showing children the advantages of learning.
First period for Barrio Sésamo on Spanish TV was short, and in 1980 the show was over. It would return again in the 1980s, but replacing Caponata and Perezgil with Muppets Espinete and Don Pimpón. Cohen would not return to the series, but she would work again with Fernando Fernán-Gómez both in Cuentos eróticos (1980, where she was the director) and Yo qué sé (1980, where she directed, wrote and produced). She also returned to TV series with more episodes of prestigious series Estudio 1.
The 1980s showed a decrease in her ratio of work per year, although she became famous enough as a hostess in La Tarde and Después de.... She had also chance to work hardly with Fernán-Gómez in some of his best movies such as Mambrú se fue a la guerra (1986), El Viaje a ninguna parte (1986) or The Sea and the Weather (1989). She worked as a director only for TV series Delirios de amor in 1989.
During the 1990s, she only worked occasionally in movies, although her choices, while few, were spectacularly good - her relationship with Fernán-Gómez had probably more than a little to do with that. Being old acquaintances and a good team, Fernán-Gómez knew how to make good use of her on-screen. She worked in The Dumbfounded King (1991) in a great role as the widow duchess of Maestrazgo, and she is also credited as collaborator for Oscar-winning Belle epoque (1992, best foreign movie, and featuring a great Fernán-Gómez).
During the late 1990s, she made her return to a childhood audience starring in animation movie ¡Qué vecinos tan animales! (1998). Her role as "Mom Mouse", next to voice actor Javier Franquelo ("Dad Mouse") and her successor in Barrio Sésamo Chelo Vivares ("Nicky Mouse", she had acted as Espinete).
On this same year, she also appeared in another of Fernán-Gómez's most prestigious movies, The Grandfather, playing the majoress. Nominated to the Best Foreign Movie Oscar, the movie lost to Italian Life is Beautiful.
On 2000, 54-year-old Cohen married 79-year-old Fernán-Gómez. It was Cohen's only marriage, but Fernán-Gómez's second one - he had been married from 1945 to 1959.
Her last roles were roles for movies such as Bibliofrenia (2003) and Oculto (2005), usually only in projects where Fernán-Gómez has also been involved. She was a journalist for Spanish newspaper El Mundo.