Irish football legend Robbie Keane brought the curtain down on over two decades as a player on Wednesday saying his career had exceeded all his hopes when he was a "football-mad boy growing up in Dublin".

The 38-year-old -- his country's record goalscorer on 68 well clear of Niall Quinn who is next with 21 -- is to focus on his new duties as assistant manager to new Ireland handler Mick McCarthy.

Keane, who replaces Roy Keane (no relation) in the role after the latter and manager Martin O'Neill were fired last week, captained Ireland for a decade until his retirement from the national team in Aug. 2016.

"Today, after 23 wonderful years, I am formally announcing my retirement as a professional footballer," Keane said in a statement.

"From Crumlin United around the world to the likes of Milan, London and Los Angeles, I could never have imagined the path my football life would take.

"It has exceeded all the hopes I had as a football-mad boy growing up in Dublin."

Keane, unlike his near namesake, enjoyed good relations with McCarthy in the latter's first spell in charge of the national side.

He was one of their stars at the 2002 World Cup -- which infamously saw their one world class player Roy Keane sent home after launching a tirade of abuse at McCarthy -- where the Irish went out on penalties in the last 16 to Spain.

Keane also enjoyed a highly successful, if peripatetic, club career which ended with a period as player/manager at Indian outfit ATK, in the season that finished in March.

In all, Keane scored 126 goals in 349 Premier League matches, 91 of them for Tottenham Hotspur, although he also had spells with Coventry, Leeds United and Liverpool in the elite league.

"Leaving home at 15 years of age to pursue my professional career in England seems a lifetime ago now," said Keane.

"I was a street footballer full of hope armed with huge ambitions and a determination to succeed.

"All I needed was that one chance."

Keane had especially warm words for his long service to his country on the pitch -- winning 146 caps and aside from the 2002 World Cup appearing also in two European Championships.

"Playing and captaining my country has been the highlight of my career," said Keane.

"I enjoyed every moment of the most incredible journey with the Ireland team over an 18-year period and as I have said many times before, words cannot express how proud I am to be Irish."