Portrush, Northern Ireland, June 28, 2012 (AFP) - Singh, 40, birdied six of his opening nine holes and made it three birdies in succession when he birdied the 10th before dropping a shot at the 14th but ending his round with a birdie at the last in the rain and lightning-affected event.
He was later joined by 30-year-old Frenchman Gregory Bourdy who birdied three of his opening four holes in a bogey free display.
Singh's starting round is his best opening score since a similar 65 to commence the Maybank Malaysian Open earlier this year, and enroute to finishing 11th in Kuala Lumpur.
Bourdy's round is his best all year. 
Singh is visiting Northern Ireland for the first time and he spoke of his joy in competing on a links course after having made his link's debut as a then 16-year-old in the 1988 British Amateur championship at Royal Porthcawl in Wales.
"I've always loved playing on links courses as you get to play some remarkable shots where you pitch it 20-yards short of the green, and where you don't always have to go with the driver," he said.
"You can elect to play it short and then play these low bump-and-run shots into greens, so you need feel and imagination in playing links golf and I just love that.
"Growing up I never played links golf but then I went to British Amateur qualifying about 20 years ago and just enjoyed every bit of it."
While Singh is seeking to win only a fourth European Tour title, as well as ending a four-year winless drought, he also spoke of his quest of qualifying for the 2016 Rio de Janeiro Olympic Games, when golf returns to the Olympics for the first time since 1904.
"I would love to represent India in the 2016 Olympics and not only because of what my father did but because golf is returning to the Olympics," he said.
"So if I can qualify for the Rio Olympics that would be fantastic but I will have to be ranked inside the top-100 on the World Rankings."
The former double Asian Tour No. 1 Singh is currently ranked 187th in the world with his career best ranking being as high as 28th in March 2009.
His goal to represent India in golf has also been heightened not only by the fact his now 82-year old father, Milka was a three-time Olympic sprinter but also with thr news a movie on his father's life will be released next January 26.
"It's about his life history from his childhood till he ran," Singh said.
Three players, the England pair of Mark Foster and Andrew Marshall, along with Australia's Matthew Zions share second place on six under par.
Triple major winning Padraig Harrington quickly stamped his claim for a second Irish Open title with a five-under-par 67 on the opening day of the event.
Harrington, winner of the event in 2007 at Adare Manor, recorded six birdies and just one bogey as he seeks to also end a four-year winless drought.
"I am very, very happy with the score and certainly would have taken that going out," said Harrington.
"It keeps me well in position with the only disappointment, and taking some of the shine off my round, was the three-putt for bogey at the last."
England's James Morrison continued his good form with a hole-in-one at the par three, 14th hole.
It is the 26-year old Morrison's first ace on the European Tour and comes just three days after he finished the leading player in Monday's British Open 36-hole qualifier at Sunningdale.
Scores of the first round of the Irish Open at Royal Portrush here on Thursday (Gbr & Irl unless stated, par 72):
65 - Jeev Milkha Singh (IND), Gregory Bourdy (FRA)
66 - Mikko Ilonen (FIN), Andrew Marshall, Matthew Zions (AUS), Edouard Dubois (FRA), Mark Foster, Oscar Floren (SWE)
67 - Peter Whiteford, Nicolas Colsaerts (BEL), Warren Abery (RSA), Simon Dyson, Thongchai Jaidee (THA), Anthony Wall, Michael Jonzon (SWE), Keith Horne (RSA), Alejandro Canizares (ESP), Padraig Harrington
68 - Alex Haindl (RSA), Richard Bland, Carlos Del Moral (ESP), Gary Orr, Ross Fisher, James Morrison, Emiliano Grillo (ARG), Thomas Norret (DEN), Mark O'sullivan, Jamie Donaldson, Lorenzo Gagli (ITA), Dylan Frittelli (RSA), Fredrik Andersson Hed (SWE), Bradley Dredge
69 - Andrew Johnston, Mikael Lundberg (SWE), Robert Jan Derksen (NED), Ricardo Santos (POR), Steven O'Hara, Graeme Storm, Jose-Maria Olazabal (ESP), Christian Nilsson (SWE), Steve Webster, Richie Ramsay, Paul Waring, Marcel Siem (GER), David Lynn, Mark Murphy, Romain Wattel (FRA), Paul Lawrie, Jbe Kruger (RSA), Rich Beem (USA), Fabrizio Zanotti (PAR), Paul McGinley
70 - Francesco Molinari (ITA), Garth Mulroy (RSA), Robert Coles, Peter Hedblom (SWE), Kenneth Ferrie, Jose Manuel Lara (ESP), John Daly (USA), Paul Cutler, Joel Sjoholm (SWE), Rory McIlroy, Simon Thornton, Michael Hoey, Jamie Moul, Estanislao Goya (ARG), Matthew Baldwin, Lee Slattery, David Drysdale, Thomas Levet (FRA), Richard Sterne (RSA)
71 - Jaco Van Zyl (RSA), Felipe Aguilar (CHI), Gary Boyd, Robert Rock, Daniel Denison, Marc Warren, Niclas Fasth (SWE), Markus Brier (AUT), Sam Little, Rafael Cabrera Bello (ESP), Gonzalo Fdez-Castano (ESP), Graeme McDowell, David Howell, Matthew Nixon, Phillip Price, David Horsey, Dermot Mcelroy, Darren Clarke, Ricardo Gonzalez (ARG)
Selected
72 - James Kingston (RSA), Hennie Otto (RSA), Darren Fichardt (RSA), Brett Rumford (AUS)
73 - Michael Campbell (NZL), Keegan Bradley (USA), Richard Green (AUS)
74 - Tjaart Van Der Walt (RSA), Shiv Kapur (IND), David Dixon, Julien Guerrier (FRA), Matthew Southgate, Pablo Martin (ESP), Oliver Fisher
75 - Soren Kjeldsen (DEN), Gareth Maybin, Branden Grace (RSA), Rhys Davies, Andrew Dodt (AUS)
76 - Colin Montgomerie
77 - Daniel Miernicki (USA)
78 - George Coetzee (RSA), Shiv Shankar Prasad Chowrasia (IND)