Interim head coach Steve Spagnuolo announced the decision Wednesday after the Giants practiced for the first time since the housecleaning firings of head coach Ben McAdoo and general manager Jerry Reese.
The firings on Monday by owner John Mara -- less than a week after the benching of Manning for Geno Smith created a backlash from fans -- ended a tumultuous week for the 2-10 Giants, who are going through one of the worst seasons in franchise history
"Eli Manning will be the quarterback for this football team and this game," Spagnuolo said as he addressed the media for the first time as interim head coach at the team's training facility in East Rutherford, N.J.
"When Mr. John Mara and I talked, one of the first things he asked was about the quarterback situation, and I said, 'John, my gut is right now Eli should be the starter.'"
Manning took the first-team snaps at Wednesday's practice. Smith is expected to return in a backup role while rookie Davis Webb remains the third-stringer.
Smith started Sunday's 24-17 road loss to the Oakland Raiders after Manning was benched by McAdoo, completing 21 of 34 passes for 212 yards with one touchdown and two fumbles.
"It's been a rough 60 hours since we left Oakland, needless to say," said Spagnuolo, also the defensive coordinator.
Manning, who started 210 straight games for the Giants, fought back tears last week as he talked about the stunning decision by McAdoo to name Smith the starting quarterback against the Raiders.
In an interview with WFAN Radio in New York on Monday, the 36-year-old Manning said he talked to Spagnuolo and told him he wanted to start.
"I do not know for certain if I'm starting. I hope I am," Manning told WFAN. "I did speak with Coach Spags for a little bit, told him I wanted to be starting QB, be out there and win these four games. He said he appreciated that and was going to talk with the offensive guys, and I hope I'm out there against the Dallas Cowboys."
Manning has thrown for 2,411 yards with 14 touchdown passes and seven interceptions in 11 games this season.
The Giants finish with three of their final four games at home -- hosting Dallas at MetLife Stadium on Sunday, Philadelphia on Dec. 17 and Washington on Dec. 31. The Giants also play at Arizona on Dec. 24.
Spagnuolo said safeties coach Dave Merritt will help him with the defense as he concentrates on his interim head coaching duties.
"I will give it every ounce of energy I have," Spagnuolo said.
Mara held a news conference Monday afternoon to explain the firings after discussions with co-owner Steve Tisch.
"We've kind of been spiraling out control here. I just felt like we needed a complete overhaul.
"This has been the perfect storm this season. Everything that could have gone wrong this season has gone wrong."