|The 38-year-old is poised to become the country's youngest ever Taoiseach|
The 38-year-old son of an immigrant doctor is poised to succeed outgoing Taoiseach Enda Kenny, after being elected as leader of Fine Gael.
Mr Varadkar saw off a challenge for the top job from Simon Coveney, a 44-year-old father-of-three from Cork.
|Leo Varadkar is congratulated by his challenger for the top job, Simon Coveney|
He is expected to be formally confirmed as Ireland's new leader when the Dail parliament resumes on 13 June.
So who is Leo Varadkar?
It was Sunday, 18 January, 2015, Ireland was preparing for a referendum on same-sex marriage and cabinet minister Leo Varadkar was about to go public.
"I am a gay man. It's not a secret but not something that everyone would necessarily know, but isn't something I've spoken publicly about before," he told listeners to RTE radio.
"It's not something that defines me. I'm not a half-Indian politician, or a doctor politician or a gay politician for that matter. It's just part of who I am. It doesn't define me."
|His election as Enda Kenny's successor represents a changing of the guard in Irish politics|
His election as Enda Kenny's successor represents a changing of the guard in Irish politics
At the age of 38, he is poised to become the country's youngest ever Taoiseach.
His election as Enda Kenny's successor represents a changing of the guard in Irish politics.
Tanaiste (Deputy Prime Minister) Frances Fitzgerald TD, said: "I've known Leo for well over 20 years. He blazed a trail through young Fine Gael.
"He's a very original thinker and I think his own journey reflects the journey of Ireland in a way, in terms of inclusion and diversity."
|With Brexit fast approaching, Mr Varadkar's political honeymoon won't last long.|
But having already held three cabinet posts - transport, health and welfare, no one seems terribly surprised by his swift rise to the top of government.
At Kings Hospital School in his Dublin West constituency, they are celebrating the fact that one of their alumni is expected to be ratified as Prime Minister.
With Brexit fast approaching, Mr Varadkar's political honeymoon won't last long.
The honours board in the school records his distinction in the entrance exam for medicine and he went on to graduate in it, but teachers recall a passion for politics.
History teacher John Huggard said: "Leo was his own man. He was well able to challenge opinions you might give but he would always back them up with facts.
"He was a lively class debater. I think he'll challenge various aspects of government but I also think he'll take counsel."
Having won a hard-fought contest, his first challenge will be to unite Fine Gael around his leadership, but with Brexit fast approaching, Leo Varadkar's honeymoon won't last long.