The quarterback immediately led the Seahawks to a touchdown on a seven-play, 75-yard drive that included a 51-yard completion to tight end Noah Fant. Ken Walker finished off the drive with a 1-yard touchdown run.
The Giants have been outscored 77-9 in the first half this season, the only team without a first half touchdown.
Smith, who is questionable to return, completed 9 of 11 passes for 67 yards and a touchdown. DK Metcalf had the 6-yard touchdown reception, which completed a two-play, 7-yard drive set up by Mario Edwards' strip-sack and Jordyn Brooks' recovery of Daniel Jones' fumble.
Jones is 14-of-17 for 151 yards and has 26 yards rushing on four carries.
Both teams have 155 yards.