The Taoiseach, Mr Ahern, paid a private visit to Mr Billy Burke, who suffers from cystic fibrosis, at his home in Killorglin, Co Kerry, yesterday.
The visit was made in response to a direct appeal this week by a Burke family friend and it lasted longer than scheduled.
Mr Ahern travelled to Killorglin to meet Mr Burke after addressing the IMI conference in Killarney. He was scheduled to spend just 10 minutes but stayed for almost 40 in the specially set- out apartment in the Burke home.
Mr Burke is suffering from a cold and has been feeling unwell in recent days, but was said last night to have been buoyed by the visit.
A rally held in Killorglin earlier in the week, asking the Minister for Health, Mr Martin, to intervene to ensure Mr Burke received a transplant, drew more than 5,000 people.
The Minister for Arts, Mr O'Donoghue, who is the constituency's Fianna Fáil TD, attended the rally on Monday, at which Mr Burke's sister, Ms Lisa Burke, and others made direct appeals to him.
Ms Anne Foley, a family friend, confirmed she did not contact either Mr Martin or Mr O'Donoghue but instead went straight to the Taoiseach's adviser.
"I needed Bertie Ahern to meet Billy Burke. I feel anybody who went into the room to meet him came out a different person," she said yesterday.
She did not wish to comment further on the visit other than to say the family was delighted Mr Ahern took time out from a busy schedule to meet Mr Burke.
The visit was intended to be private by agreement and the media were not informed.
The 29-year-old accountant is awaiting a double lung transplant but has been taken off the list at Freeman Hospital Newcastle, which receives the Irish pool of lungs, on medical grounds.
The Wythenshawe hospital in Manchester has said it will carry out the transplant and has placed Mr Burke on a list there.