Gylfi Gröndal was born in Reykjavík on April 17, 1936. He studied Icelandic at The University of Iceland, and then took up a career in journalism. He worked as a journalist for more than thirty years, editing papers such as the magazines Fálkinn, Vikan and Samvinnan and the newspaper Alþýðublaðið. He also did numerous radio programs about 20th century writers for The Icelandic Broadcast Company.
For most of his career, Gylfi was first and foremost a writer. He started writing poetry at a young age, and his first published poems appeared in the collection Ljóð ungra skálda (Poems by Young Poets) in 1954, when he was 18 years old, followed by some poems in the collection Árbók skálda (The Poetry Yearbook) in 1956. He sent forward seven book of poetry, the last one was Eitt vor enn (One More Spring) in 2005. His poems have also appeared in collections in Iceland and abroad. Gylfi is however best known for his interview books and biographies that are close to 30 in number. Among them are biographies of the three first presidents of Iceland and he has also written a number of books about women, especially some who were ahead of their time regarding gender equality. The first volume of his biography about the poet Steinn Steinarr was nominated for the Icelandic Literature Prize in 2000. The latter was published a year later.
Gylfi Gröndal passed away on October 29, 2006. He was married to Þóranna Tómasdóttir who is a high school teacher, and they have three children.