The Masters champion is tied at the top of the leaderboard in southern Spain with Dutchman Joost Luiten after carding seven birdies.
Garcia on his Andalucian Day 1
"The game was on pretty much all day. I hit my irons very well, I didn't drive the ball well on the eighth hole but I was pretty much spot on there and I made some nice putts here and there," Garcia told europeantour.com.
"It was gettable because it was soft but you still had to hit good shots and I was able to do that for the most part of the day. I'm very happy with my round."
Four par threes. Four birdies.— The European Tour (@EuropeanTour) 19 October 2017
The first man to do that in this event. ✊ pic.twitter.com/RPXw8kiQrY
Sergio Garcia Foundation as Masters host
The 37-year-old is hosting the first staging of the event since he won the title in 2011, with the tournament having been cut the following year due to funding problems.
The Spaniard is looking for a first win since claiming his long-awaited first major title at Augusta National in April, but he carded four birdies on his front nine after starting on the 10th hole. A bogey at the eighth took some shine off Garcia's round, after he had rolled in three birdies in four holes on his inward half.
The world number 11 is second in the European Tour's Race to Dubai standings behind Englishman Tommy Fleetwood, who is not playing in Spain this week, with just five events remaining this season.
World number 102 Luiten matched Garcia on the 1997 Ryder Cup course, mainly thanks to a run of five birdies in his final seven holes.
Poor start for Jon Rahm
There was disappointment, though, for world number five Jon Rahm, as the 22-year-old Spaniard stumbled to a three-over-par 74 in his first professional round on home soil.
Rahm's compatriot Pablo Larrazabal made a late charge to sit tied for second with England's Robert Rock, one shot adrift of the leading duo.
Leaderboard after Day 1
|1. Sergio García||-5|
|-. Joost Luiten (Hol)||-5|
|3. Pablo Larrazábal||-4|
|-.Robert Rock (Eng)||-4|
|5, Paul Peterson (USA)||-3|
|6.James Morrison (Eng)||-2|
|-. Andrew Johnston (Eng)||-2|
|-, Richard Finch (Eng)||-2|
|70. Jon Rahm||+3|