The American journeyman's long game was poor, by his own admission, but he putted brilliantly to post eight birdies in a six-under-par 64 on an unusually mild summer's morning at Sedgefield Country Club.
The 31-year-old Stroud led by one stroke from fellow Americans Andrew Svoboda and Robert Garrigus, and Australian Matt Jones, with half the field back in the clubhouse.
"I didn't play that great today (but) I'm in the lead. It's a weird deal," said Stroud, who is ranked 48th in the PGA Tour's FedExCup points list heading into the play-offs, which start next week.
"It's a crazy game. I only had one or two really good drives and four or five iron shots (but) kept myself in position and made a lot of good putts - not a bunch of 30-footers, just a lot from eight-to-20 feet."
Stroud made his first start as a tour pro in Greensboro, on a sponsor's invitation in 2004, and has been a regular visitor ever since, though he was planning to skip the event this year.
However, he missed the cut by one stroke at last week's PGA Championship and then decided to enter Greensboro, where he has never finished better than 57th.
"I played pretty well in the PGA and I told my caddie I'm playing too well to go home and just sit and get rusty," said Stroud, whose best PGA Tour finish was a play-off loss at the Travelers Championship in June.
"This is the nicest weather I've seen here, I'm happy to be here and it's a great golf course that's even better with new greens."
Stroud acknowledged he would have to improve his overall game to have a chance of winning on Sunday, so he headed off to the practice range to work on his flaws.
Some of the bigger names in the field also had plenty to work on after struggling to go low in the opening round. Fijian Vijay Singh shot a 70, South African Ernie Els carded a 71 and Irishman Padraig Harrington returned 73.
American world number seven Brandt Snedeker, the highest-ranked player in the field and a double winner on the 2013 PGA Tour, was along the late starters.