The pair came first in the men's lightweight double sculls final early Thursday morning Irish time.
The first half of the race had been led by the German team, but O'Donovan and McCarthy managed a surge in the second half to pip them to first place.
"The Germans and Italians always have a quick start, so for the first time we had a quick start as well, not for lack of effort," said O'Donovan. "It was a bit of a surprise that it paid off and we weren’t totally dropped in the first 500m, so that was good. And then we put the heads down and ploughed on so it was good."
"It feels pretty good," said McCarthy on winning gold. "We can’t complain! We had a really good race – but a tough one. The Germans were flying so it was hard. I was really excited when we first crossed the line and there was a bit of relief as well. We have had a good time all week, so we are a bit sad that it is all over. We hadn’t had too much time to think about it but it feels pretty good and hopefully it will be that way for a while."
On Twitter, Taoiseach Micheál Martin said the win was "A special day for Irish rowing and the Irish people."
An outstanding gold medal for Paul O’Donovan and Fintan McCarthy.
Breathtaking victory in the lightweight double sculls - a race that will live long in history.
A special day for Irish rowing and the Irish people. #Tokyo2020 https://t.co/hzhnFL8SCI
— Micheál Martin (@MichealMartinTD) July 29, 2021
President Michael D Higgins also took to twitter to congratulate the pair.
"After the magnificent success in women’s rowing yesterday, today we celebrate Ireland’s first Olympic gold medal in rowing, won so deservedly by Paul O’Donovan and Fintan McCarthy in the lightweight double sculls," wrote the president.
“After the magnificent success in women’s rowing yesterday, today we celebrate Ireland’s first Olympic gold medal in rowing, won so deservedly by Paul O'Donovan and Fintan McCarthy in the lightweight double sculls.”
— President of Ireland (@PresidentIRL) July 29, 2021
The win comes a day after another Skibbereen rower, Emily Hegarty, earned a bronze medal as part of a four-woman team.
