She had Danish ancestry on her father's side, notably her paternal great-grandfather, Jan Andresen, who had traveled alone to Porto as a boy and never left the region.

Sophia began her studies at the new Sacred Heart of Jesus College, at 1354 Avenida da Boavista, Porto, entering with the school's first class.

[1][2] In time, she became one of the most representative figures of a liberal political attitude, supporting the monarchic movement[5] and denouncing Prime minister Salazar's regime and its followers.

In 1964, Andresen received the Grand Prize of Poetry by the Portuguese Society of Writers for her book Livro Sexto.

Andersen won acclaim as a storyteller with Contos Exemplares (Exemplary Tales), "Histórias da Terra e do Mar" (Stories of Land and Sea), and a number of children's books – A Menina do Mar (The Sea Girl), O Cavaleiro da Dinamarca (The Danish Knight), A Floresta (The Forest), O Rapaz de Bronze (The Bronze Boy), A Fada Oriana (The Fairy Oriana).

She also published several poetry books and anthologies, including: Poesia, Dual, Livro Sexto, Coral, Dia do Mar, No Tempo Dividido, Grades, O Nome das Coisas, As Ilhas, Antologia, Geografia, Navegações, O Búzio de Cós.

[8] Initially, her body was buried in Carnide Cemetery, but on 20 February 2014 the Assembly of the Republic unanimously decided to honor the poet by entombing her remains in the Portuguese National Pantheon.

Andresen began her love of poetry as a child when, at the age of three, she was taught "A Nau Catrineta" by her nanny Laura.

Even a certain social and human concern, or my first awareness of the harshness of the lives of others, because this housekeeper said: "Now fishermen walk in the sea, let us pray that they will reach the land" (...).

For the author, this contact became an example of freedom, beauty, perfection and mystery and is widely found in her work, whether by the allusions to the land (trees, birds, moonlight) or by her references to the sea (beach, shells, waves).

In addition to the thematic aspects mentioned above, Fernando Pessoa's enormous influence on the work of Andresen is also present.

[18][19][20] What the two authors have in common is: Plato's influence, the appeal to infinity, childhood memory, Sebastianism and Messianism and the formal tone that evokes Álvaro de Campos.

In general, the author's thematic universe is comprehensive and can be represented by the following summary points:[16][21] Regarding Andresen's language style, the most evident marks are:[16] the hieratic value of the word, the rigorous expression, the appeal to the clarifying vision, richness of symbols and allegories, synesthesias and an evocative rhythm of a ritual dimension.

One can also notice a "transparency of the word in its relation of language to things, the luminosity of a world where intellect and rhythm harmonize in perfect, melodic form.

Eduardo Lourenço says that Andresen has a wisdom "deeper than just knowing", that its intimate knowledge is immense and its reflection, however deep, is exposed in an original simplicity.

This is why a poem speaks not of an ideal life but of a concrete one: the angle of a window, the resonance of streets, cities and rooms, the shadow cast by a wall, a sudden face, the silence, distance and brightness of the stars, the night’s breath, the scent of linden and of oregano."

Her poetry has been translated into English by Ruth Fainlight, Richard Zenith and most recently by Colin Rorrison with Margaret Jull Costa, as well as into many other world languages.