Feldek is the author of several books of poetry (Kriedový kruh, Paracelsus, and Milovanie pred usnutím), the novel Van Stiphout, and several plays including Teta na zjedenie or Jánošík podľa Vivaldiho.
He translates works of modern world poets (Alexander Blok, Vladimir Mayakovsky, or Guillaume Apollinaire) as well as classical plays (such as those by Sophocles and William Shakespeare).
In January 1989 he protested against the arrest of Václav Havel and signed a political manifesto A Couple of Sentences.
In 1992, Feldek publicly noted that "Dušan Slobodník became Minister of Culture and his fascist past immediately came to light", referencing to his involvement in an SS training course as a teenager (at the age of 17) in Sekule at the time of the First Slovak Republic.
Feldek has also written the poem Dobrú noc, má milá, containing the verse "esesák sa objal s eštébákom" (an SS man gave a hug to an STB agent), referencing to the disputed past of both Dušan Slobodník and Prime Minister Vladimír Mečiar.