The Minister for Agriculture and Food Mr Walsh is to retire from the Cabinet in September.
Bertie Ahern
Mr Walsh, who is 61, has told the Taoiseach he did not want to be included in the cabinet in next month's reshuffle and said he would not be seeking reelection to the Dáil at the next election.
Praising Mr Walsh, who was first elected to the Dáil in 1977, the Taoiseach, Mr Ahern described his tenure as a minister as "unique" in modern Irish politics and said his contribution to rural Ireland and to the farming community in particular, was "enormous".
"He provided clear-sighted leadership through times of enormous change and challenge. While others regularly predicted the demise of rural Ireland he remained steadfast in his optimism and in his practical commitment.
"As Minister Joe Walsh has presided over the development of an internationally competitive and sophisticated agri food industry, the food safety agenda has also been a major issue in recent years," The Taoiseach said.
"While these long-term achievements will be his lasting legacy, it was the Foot and Mouth crisis that was Joe Walsh's finest hour," continued Mr Ahern. "The consequences of failure to stop Foot and Mouth would have been devastating not only for farmers but for the whole economy. Typically calm and resolute, he successfully faced down what was a potential national catastrophe".
Fine Gael's agriculture spokesman, Mr Billy Timmins, wished said he wished Mr Walsh and his family well on behalf of the party.
"Joe Walsh has been to the forefront of Irish Agriculture for almost two decades, at a ministerial level throughout most of the 90s until the present day, and has overseen the many changes which the industry has undergone.
He will be best remembered for his handling of the foot-and-mouth crisis, which posed the greatest threat to Irish agriculture in recent times.
"It is important now that the Taoiseach considers this vital appointment and ensures that Minister Walsh's replacement is capable of leading the sector through the many challenges facing Irish Agriculture, not least CAP reform and increased competition in the world food market. It is essential now that the agriculture portfolio has a firm hand on the tiller to steer the industry through the changing environment ahead."
Labour's agriculture spokeswoman, Dr Mary Upton, said she wished Mr Walsh the very best for the future following his announcement today.
"Having marked him as Opposition spokesperson in agriculture for over two years, I know him to be courteous, polite and very co-operative with the Opposition.
"Joe Walsh was an effective Minister for Agriculture in many respects, not least in his competent handling of the foot-and-mouth crisis a few years ago, and he had a strong passion for his portfolio," she said.
"Irish agriculture, however, has changed dramatically in the past few years, not least in relation to CAP reform and Joe Walsh's successor will face a number of significant challenges in the coming years."
The president of Macra, Mr Thomas Honner, said Mr Walsh had made a "huge contribution" to Irish agriculture over the past two decades.
He said that while farmers had the occasional disagreement with Mr Walsh, his relationship with farmers had by and large been positive.
"As the longest-serving Minister for Agriculture in Europe, Mr Walsh has successfully negotiated a number of complex EU agriculture reform packages which, for the most part, have been good for reland," he added.
He said, however, it was crucial that Mr Walsh secured the best possible outcome for farmers on the implementation of the Nitrates Directive prior to his retirement.