Talented GAA player Eoghan (21) was from Rathfarnham and studied at St Mary's College in Rathmines until 2012.
He is survived by his parents, Gerry and Mary, and brothers, Stephen and Andy. He had just completed his third year studying Supply Change Management and Logistics at DIT Aungier Street.
Eoghan has been described as a 'life-long GAA fan' and had been a member of the Ballyboden St Enda's club since childhood, having played football for its intermediate and junior teams (inset).
The GAA club has paid tribute to Eoghan, saying he was very popular with his team mates.
Today, his girlfriend Sarah McCarthy posted a message on Facebook to express her sense of loss.
"No words can begin to describe the loss I feel. I've lost the love of my life and my best friend," she wrote.
This morning, John Murray also paid tribute to Eoghan on his RTE radio show.
"As the events unfolded I also discovered that the tragedy was even closer to home," he said. "The brother of one of my son's good friends, Eoghan Culligan was dead. And I'm thinking of the Culligan family and the other families as they make that lonely and painful journey to Berkeley."
The chaplain at DIT, where Eoghan was studying, described the incident as "incredibly tragic".
"It was a day of incredible emotion, so many students on Facebook were posting that they got their exams online... and then another strain started coming in about what was happening in America," Fr Alan Hilliard told Newstalk.
"When anything like this happens, the college does have the question are our students involved, and then you hear they are. It is just incredibly tragic," he said.
"These people had their lives ahead of them and, all of a sudden, it's gone, it's cut short. I suppose everyone is just numb, just shocked at the same time.
"From my experience with working with immigrant communities, I know that the community will bond, they will open their hearts, doors and resources to the Irish people who are struggling," he continued.
"It's times like this when you see how fragile life is, how disconnected you are, even though the modern world is telling you you're close with just a Skype call away. This is when friends become family."