Anthony Flynn has wanted to give blood “for most of his adult life”.
On Monday, he was able to do it.
As of 16 August, men in Northern Ireland who have been in a same-sex relationship for more than three months can donate blood.
Previously men who had been in a same-sex relationship had to wait for a year after their last sexual activity before donating blood.
The new rules bring Northern Ireland into line with the rest of the UK.
The Green Party NI councillor said: “Unfortunately I was unable to because of the eligibility criteria that was before today.
“It’s a very rewarding experience and, thankfully, I’ve given some blood today that’ll hopefully go on to save a life.”
The Northern Ireland Blood Transfusion Service has said the need for donations has never been greater.