Francesco Molinari's 68 was the best of those heading to Medinah Country Club outside Chicago in two weeks' time for the biennial contest between Europe and the United States.
The Italian was two shots better off than Europe team mate Martin Kaymer of Germany, while France's Nicolas Colsaerts was a further shot adrift.
Sjoholm described his eight-under-par round as "fighting" rather than "solid", but said it made up for missing the cut in his past two tournaments.
"I want revenge," he told the European Tour website (europeantour.com). "The last two weeks I actually played quite good golf.
"Normally when I score well, I have to putt well. The last few weeks I've putted quite poorly and missed the cut by one stroke. Both times I felt like I had a good chance to make the cut, but you have to forget and keep moving on.
"I hit it basically everywhere. I was in the woods a lot and made some funny birdies today. It was a big, fighting 64 rather than a solid 64, but it's great fun to be eight under."
England's Lee Slattery finished the day a shot off the lead with countryman Richard McEvoy and South Africa's Garth Mulroy a further shot back.