President Michael D Higgins has hailed the strength of the country's film industry on a night when home-grown talent was strongly represented at the Oscars.
Brooklyn star Saoirse Ronan, 21, missed out to Brie Larson in the best actress category (for her role in Emma O'Donoghue's Room) but showed her roots in her dress choice.
"I wore green at my first Oscars as well. I wanted to wear green because I'm very proud to be Irish and Calvin Klein made this for me," she said.
Other Irish nominees included Steve Jobs star Michael Fassbender, who was pipped to the best actor Oscar by The Revenant's Leonardo DiCaprio, and Lenny Abrahamson, who was nominated for best director for Room.
The Revenant director Alejandro Inarritu won that gong but Larson's best actress Oscar was for her role in Abrahamson's film.
And the Irish did not go home empty handed as director Benjamin Cleary's movie Stutterer won the Oscar for best live action short film.
Brie Larson's Oscar was for her performance in Room, directed by Irishman Lenny Abrahmson and produced by Irish film company Element Pictures.
In his acceptance speech Dubliner Cleary said: "You know, when you make your first ever film, you've got to convince a lot of people to jump on board and take a risk with a first-time director, and, you know, to every single member of the cast and crew of Stutterer for jumping on board and taking that risk with me, I'm forever grateful.
"And to the Academy for this award. It's such a huge honour. Thank you so much. To my amazing parents for all the support, thank you."
Cleary also paid tribute to the stars of the film, about a man with a crippling stutter and his online relationship with a woman.
"Chloe Pirrie, you're amazing, wherever you are up there. Matthew - to the wonderful Matthew Needham, you are this film, brother, thank you so much."
Cleary finished by declaring: "Every day is a proud day to be Irish, but today even more so than usual. To everyone for all the support back home, thank you so much."
Speaking on the red carpet, Ronan said attending the Academy Awards was "surreal".
And she paid homage to the other actresses nominated in her category, including Carol star Cate Blanchett and 45 Years star Charlotte Rampling.
She said: "You've got people like Cate as well, and Charlotte, who have been in the game for such a long time, and have such an incredible body of work. To be put in the category with them for anything is wonderful."
President Higgins has said the strong line-up of Irish actors and film-makers was a "tribute to the Irish film industry".
Mr Higgins said: "It is now accepted internationally that Ireland has an accomplished film industry, providing a great return from the investment in film - made over recent decades - through highly skilled jobs and an enhanced international reputation."
Also commenting on the win, Bord Scannán na hÉireann/the Irish Film Board Chief Executive James Hickey said:
"Congratulations to Benjamin Cleary and Brie Larson on winning these prestigious awards.
"This award for Benjamin emphasises that the next generation of Irish filmmaking is in very good shape. Ireland has a very strong history in this category with ten short film nominations and one win since 2002, eight films of which were funded by the Irish Film Board.
"Brie's much deserved win is a credit to Lenny Abrahamson and the entire team behind the Irish film ROOM produced by Element Pictures, which has become an international hit. I'm particularly proud of the fact that two out of the five nominees in the Best Actress category were for roles in Irish films."
An unprecedented nine Irish nominations- seven of which are Irish Film Board supported - featured in the event, which was watched by an estimated 950 million worldwide and will be televised on Irish TV tonight.
"The nine Irish Oscar nominees associated with Ireland and Irish film are all world-class players who have been recognised for their talent at the most prestigious of film awards. Behind each nomination is a team of talent who should be justifiably proud, irrespective of the final outcome at the Awards," said James Hickey.
“Last night’s Oscars was a momentous milestone for the Irish film sector and we are all very proud of what the nominees have achieved. They are wonderful ambassadors for Irish creative talent and innovation. The excitement around Irish creative talent in Los Angeles in the past week has been fantastic. The success of Irish talent at this year’s award season – starting in Cannes last year and bringing us all the way to the Oscars has put a focus on Irish creative talent.
"The international recognition is also a ‘win' for Ireland, with the spotlight firmly on Irish creative talent as a result of all the nominations for Irish talent. Leading film publications in the USA are profiling Ireland ahead of the Oscars, including Variety, which hailed Ireland as a ‘Capital of filmmaking."
The role of the Irish Film Board is to support the development and production of Irish film, television drama, documentary and animation. Given the sustained long-term investment that has contributed to the success of Irish creative talent in this year’s Academy Awards, the Irish Film Board is calling on the Government to fully restore its funding. It is currently 40% less than in 2008.
Benjamin Cleary also wrote the IFB funded animated short film "The Great Fall" currently in post-production and expected to premiere later this year.
Irish nominees in the 88th Academy Awards® were follows:
Best Picture: Room, Brooklyn
Best Director: Lenny Abrahamson (Room)
Best Screenwriter: Emma Donoghue (Room) Nick Hornby (Brooklyn)
Best Actress: Saoirse Ronan (Brooklyn) and Brie Larson (Room)
Best Actor: Michael Fassbender (Steve Jobs)
Best Short Film (Live Action): Stutterer, Ben Cleary