Using the nom de plume "Doll", he appeared regularly in the newspaper, where he created satirical cartoons.
He was also known as creator of the 1960s Irish language television series Dáithí Lacha, and Rí Rá agus Ruaille Buaille.
Ó Riain was born in Lucan, Dublin to Edmund and Nora Ryan.
His father, a member of the Garda Síochána (police), took a posting in Arranmore, County Donegal in order to foster his son's interest in the Irish language.
[1] In 1977, he was confined in Mountjoy Prison having been fined for refusing to pay his television licence in protest at what he saw as RTÉ's neglect of the Irish language.