Leonard was born John Keyes Byrne in Dalkey, Co Dublin
Irish playwright and commentator Hugh Leonard, whose father-and-son drama Da won acclaim on Broadway and was made into a film, has died at the age of 82.
He had been receiving hospital treatment for some time and died in the Irish capital, Dublin.
Irish leaders praised Leonard's work both as a playwright and a journalist.
The 1988 film of Da featured Martin Sheen and the late American actor "Barnard" Hughes, who first starred in the Broadway production.
"Hugh will be greatly missed by all who had the pleasure of his company and counsel throughout the years," said Irish President Mary McAleese.
"[He] infused his work with a unique wit, all the while demonstrating a great intuition, perceptiveness and forgiveness of human nature."
The Taoiseach (Irish prime minister), Brian Cowen, recalled a newspaper column by Leonard.
"His Curmudgeon column which ran for many years in the Sunday Independent was required reading and was always guaranteed to raise a smile," he said.
"Hugh will be remembered as a great literary figure of modern Ireland," he added.
Leonard was born John Keyes Byrne but took on his pen name in the 1950s to hide from his Irish civil service employers his double life as an aspiring, outspoken writer.
His plays included The Big Birthday, A Leap in the Dark, Stephen D, The Poker Session, The Patrick Pearse Motel and The Au Pair Man.