The Tykes earned their first Oakwell point this season in what proved to be another frustrating afternoon for Leicester manager Sven-Goran Eriksson.
Eriksson's side fell behind to midfielder Butterfield's diving header in the 38th minute and, although Foxes substitute Andy King equalised 30 seconds into the second period, Leicester could not find a winner.
The big-spending promotion favourites have now won only two of their first six matches of the campaign.
Leicester handed a debut to striker Jermaine Beckford and he had a hand in King's goal, but Eriksson was indebted to his goalkeeper Kasper Schmeichel, who twice pulled off superb saves in the closing stages to deny Barnsley substitute Danny Haynes and Jim O'Brien.
Winger O'Brien returned to Barnsley's starting line-up, while midfielder Paul Gallagher was recalled for Leicester.
Former Leeds striker Beckford had the Foxes' first effort on goal, curling a 20-yard shot wide in the 10th minute, and then saw his angled shot from inside the penalty area held by Barnsley goalkeeper Luke Steele.
Gelson Fernandes was next to test Steele, this time from 25 yards, but the Tykes keeper was equal to it.
Barnsley responded with midfield trio David Perkins, Danny Drinkwater and O'Brien peppering the Leicester goal.
Drinkwater, on loan from Manchester United, was just off target with a 30-yard free-kick and striker Andy Gray headed O'Brien's cross wide soon after as Barnsley looked the more likely to make the breakthrough.
Barnsley duly took the lead their approach play deserved in the 38th minute when Gray headed Jim McNulty's cross against the woodwork and Butterfield reacted quickest to send a diving header into the bottom corner from the rebound.
Steele held another long-range effort from Fernandes as half-time approached, but Leicester went in at the break a goal down.
But within 30 seconds of the restart they were level. Beckford did well to pull the ball back from the by-line and half-time substitute King swept the ball home into the bottom corner from six yards.
Leicester goalkeeper Schmeichel then kept the Foxes on level terms, holding Tykes midfielder Matty Done's stinging shot.
A free-flowing encounter then saw King go close to a second, but he pulled his left-footed shot from inside the area wide of Steele's post.
Schmeichel denied Barnsley again in the 65th minute when he dived low to keep out an angled shot from Butterfield, who then crossed for defender Stephen Foster to head just wide.
Tykes manager Keith Hill sensed three points were there for the taking when he sent on striker Danny Haynes for midfielder Done in the 78th minute.
But Steele had to be at his acrobatic best again to keep out Richie Wellens' goalbound corner in the 82nd minute.
Barnsley pushed forward in search of the winner as the clock ticked down and almost snatched it when Haynes and then O'Brien fired in shots in quick succession, only for Schmeichel to rescue his side.