Colin Farrell has raised €774,000 (£644,000) for a charity supporting people with a rare skin condition by running the Dublin marathon while pushing one of the oldest survivors of the disease in Ireland around part of the course in her wheelchair.

The actor, who was born in the Irish capital, raised the money for Debra Ireland, an organisation that supports people with the incurable genetic condition epidermolysis bullosa (EB), or “butterfly skin”, which causes people to have very fragile and blistering skin.

He pushed his friend Emma Fogarty, 40, around the last four kilometres of the course – one kilometre for each decade of her life with the condition.

She gently hugged Farrell after they crossed the finish line to huge cheers.

“The support out there was incredible because it gave you a little bump and you would actually go a little bit faster than you should be going,” he said after placing a marathon medal over Fogarty’s shoulders.

Crouching beside her, he explained why he had taken the cause on. “It all started with how you found a way to live with EB and live not as a victim of EB,” he said. “As someone who struggled and experiences pain as a result of it, but not as a victim of it. Even though you suffer with it, you have had a full life, that has more pain than should be experienced by any human being.”

Fogarty was born with no skin on her left foot and her right arm and can develop painful blisters from just the slightest touch. She and Farrell, who has become a friend, had originally hoped to raise €400,000 and then increased their target to €1m before Sunday’s race.

Appearing on Irish TV’s Late Late Show before the run, Farrell spoke about his sobriety and health and determination to complete the run with his friend.

He finished the run in a time of 4hrs 6m 45s and said: “I have known Emma for many years and she epitomises bravery, she is what courage and pure determination are all about. That run was nothing compared to the pain she is forced to endure every single day, even though she doesn’t show it.”

Debra’s chief executive, Jimmy Fearon, told RTÉ radio: “The marathon generated unbelievable publicity for us as a small organisation.” He said EB was often described as “the worst condition you’ve never heard of”.

With the funds raised, the charity plans to expand family support services, including home visits and daily or bi-daily bandaging.