President Michael D Higgins presents the seal of the Taoiseach and the seal of the Government to Taoiseach Leo Varadkar pic.twitter.com/66vSL1wVmN— RTÉ News (@rtenews) 14 June 2017
Ironically Varadkar's appointment as Taoiseach comes only days after the Democratic Unionist Party (DUP) — which has managed to block gay marriage in Northern Ireland — was brought in to prop up British Prime Minister Theresa May, after she fell short of a majority in Parliament.
Varadkar, from the ruling Fine Gael party, said: "The government I lead will not be left or right. The government I will lead will be one of the new European center."
He was elected by 57 votes to 50 in the Irish Parliament, the Dail.
The Opposition party, of Fianna Fail, led by Micheal Martin, abstained in order to allow Varadkar to take over as Taoiseach.
In 1993 the Irish Republic was a strictly Roman Catholic state where homosexual acts were illegal and the population was overwhelmingly white and ethnically Celtic.
But in 2017 Varadkar's sexuality was not even an issue and nor was his ethnicity — his father, Ashok, a doctor, was born in Mumbai.
He moved to England in the 1960s, met his mother Miriam, a nurse, and then in 1973 moved to Dublin.
Ireland has elected Leo Varadkar as PM, gay son of Indian immigrant.— Scott Nelson (@SocialistVoice) 12 June 2017
Unelected PM Theresa May does a deal with homophobic and racist DUP. pic.twitter.com/fGntyuVV0m
Leo was born in 1979 and grew up as a 100 percent Dubliner.
He went to a private school run by the Anglican Church of Ireland and became interested in politics as a teenager.
Ireland has two main political parties — Fine Gael and Fianna Fail — and the division between the two dates back to the creation of the Irish state.
Between 1919 and 1921 the Irish Republican Army (IRA) fought a guerrilla war against the British forces who occupied the island of Ireland.
In 1922, a treaty was signed, setting up the Irish Free State, but it did not include the six counties of Ulster in the north, which were dominated by Protestants loyal to the British crown.
Civil war raged in the south between the Irish Free State, led by Michael Collins, and the remainder of the IRA which refused to accept the division of Ireland.
Fianna Fail, which translates as "Soldiers of Destiny" was led by Eamon de Valera and traditionally opposed the treaty accepting the division of Ireland.
The Irish Free State became the Republic of Ireland, or Eire, in 1937 and gradually the distinction between pro- and anti-treaty sides faded.
Kenny, who had led the party since 2002, stepped down as Fine Gael in May and Varadkar beat his nearest challenger, Housing Minister Simon Coveney, who was from Cork.
Ireland remained a very conservative nation, dominated by Catholicism, where homosexuality, divorce and abortion were all frowned upon.
But all that changed in the late 1980s as liberal ideas were imported and by the mid-1990s the Celtic Tiger economy had taken off, sucking in large numbers of migrants from Britain, other parts of the EU and further afield.
Homosexual acts were legalized in 1993 and in 2015 Ireland voted in favor of same-sex marriage.
In 2015, Varadkar, who has a degree in medicine, came out as gay in an interview on Irish radio on his 36th birthday:
"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. It is just part of my character, I suppose."
Varadkar, who had spells as Transport and Health Ministers, was Minister for Social Protection until this week but has been criticized for what some believe has been a vendetta against poor people on benefits.
Over the next few months it will remain to be seen whether Fianna Fail continue to support Fine Gael in power.
If they pull out the rug Varadkar will be forced to call an election and if he loses it, he will be the prime minister with the shortest reign in Irish history.