Smith threw two touchdowns, completing 23 of 34 passes for 212 yards with no turnovers, in the Seahawks' 27-13 victory over the New York Giants on Sunday. He should have had a third TD pass if not for a Tyler Lockett drop on a would-be score.
The 32-year-old Seahawks quarterback has been a revelation this season, having spent the past seven years primarily as a back-up, before taking over from Russell Wilson after his trade to the Denver Broncos.
Smith has already this year matched his career-best 13 touchdown passes in a single season from 2014, with nine games remaining.
"He's the real deal, we're seeing it," Carroll told reporters. "There's no mystery or, 'Oh, he's going to run out of gas or something.' It's not like that.
"He knows exactly what he's doing and he shows you week in, week out, throw after throw after throw. There's nothing for us to hold him but in the highest of expectations, really.
"What a thrilling story for the kid. He just hung in there so tough and outlasted it and now he's enjoying all the fun of it. He did great."
Smith has completed 181 of 249 attempts with a 72.7 completion rate for 1,924 yards with three interceptions this season.
The Seattle QB has also rushed for 158 yards with one touchdown, but would not get caught up in the universal praise coming for him as the surprise of he season.
"Man, we just got a win today," Smith said. "We only got a chance to play one game today, and we won it.
"We've got to continue to play hard throughout the season. Every single game is going to be a test. We know that.
"We always talk about each game being a championship opportunity and so we're just going to continue to focus on it day by day, not get caught up in the outside noise - and just do what we do."
The Seahawks are top of the NFC West with a 5-3 record, ahead of the San Francisco 49ers (4-4) and the Los Angeles Rams (3-4) and the Arizona Cardinals (3-5).
The Week 8 matchup pits two of the NFL's surprise packages against one another, with the Giants 6-1 in the NFC East as the Seahawks lead the NFC West at 4-3 despite trading quarterback Russell Wilson.
Seattle have received a boost ahead of welcoming the Giants to Lumen Field, as both Metcalf and Lockett could feature.
Metcalf was carted off in last week's win against the Los Angeles Chargers with a patellar tendon injury, prompting fears he could miss an extended period.
But the wide receiver avoided surgery, and ESPN's Adam Schefter reported he would face the Giants, while NFL Network's Ian Rapoport said he has "a good chance".
Metcalf has caught only two touchdown passes this season after a career-high 12 last year, although his 418 receiving yards rank in the league's top 25.
He trails team-mate Lockett, who has 468 yards and two TDs and also should play on Sunday.
Lockett has been managing both hamstring and rib injuries, but Schefter expects him to play. Rapoport described him as "a game-time decision" but with "some optimism he goes".
Elsewhere in the NFL, early reporting on Sunday had Las Vegas Raiders receiver Davante Adams and Dallas Cowboys pass rusher Micah Parsons both on course to play despite previously being listed as questionable.
Adams, whose Raiders go to the New Orleans Saints, was ill, while Parsons has been dealing with a shoulder injury ahead of the Cowboys hosting the Chicago Bears.
ESPN and NFL Network both reported Lockett is to receive a four-year extension worth $69.2million, of which $37m is guaranteed salary.
A third-round pick by the franchise in 2015, the 28-year-old has managed 376 receptions at an average of 13 yards per catch in the NFL, while he has 37 receiving touchdowns in his career.
He has started all 16 games in the previous two seasons and finished the 2020 campaign with a career-high 100 catches, making him one of only eight players to reach three figures in the league.
His total of 1,054 receiving yards was a touch below his 2019 number of 1,057, while he had 10 touchdown catches for the second time in three years.
Quarterback Russell Wilson targeted Lockett 132 times in a campaign that came to a disappointing conclusion. They suffered a first-round exit in the playoffs, going down 30-20 in a Wild Card showdown with the Los Angeles Rams after finishing top of the NFC West with a 12-4 record.
Wilson's future has been a hot topic during the offseason. While willing to stay with the Seahawks, the eight-time Pro Bowler reportedly provided a shortlist of teams he would play for, should the franchise consider trading him.
The commitment to Lockett follows on from Seattle handing a new deal to Gabe Jackson this week, the offensive lineman who arrived this month from the Las Vegas Raiders via a trade.
Jackson received a three-year contract worth $22.575million that, due to how it is structured, eases the impact on the 2021 salary cap.
The guard started 99 out of 100 games played during his seven seasons with the Raiders, who were reportedly considering cutting Jackson before working out a deal that saw them net a fifth-round draft pick.
Wilson threw two touchdowns to take his tally to 30 for the season, joining Brett Favre and Drew Brees as the only quarterbacks in NFL history to throw 30-plus TDs in four consecutive seasons.
The seven-time Pro Bowler also earned his 93rd career win as a starter, surpassing Peyton Manning for the most by any QB in his first nine seasons in league history, per NFL Research.
Seahawks star Wilson had thrown seven interceptions since Week 7 – Seattle losing three of their four games in that period – but the Super Bowl champion and his team returned to form to claim top spot in the NFC West on Thursday.
Wilson was 23-of-28 passing for 197 yards, two touchdowns and no interceptions, while he rushed for 42 yards on 10 carries in Seattle, where the Seahawks improved to 7-3 for the season.
Kyler Murray and the Cardinals threatened another comeback following last week's stunning Hail Mary success, but the visitors were unable to take down the Seahawks.
Murray was 29 of 42 for two touchdowns and no interceptions, while he had five carries for 15 yards for the 6-4 Cardinals.
Wilson and the Seahawks set the tone early – the signal-caller connected with DK Metcalf on a 25-yard pass in the opening quarter before Arizona's Kenyan Drake rushed to level the scores in the second period.
Another TD pass from Wilson found Tyler Lockett inside the final nine minutes of the quarter – the latter joining Jerry Rice as the only players in the Super Bowl era with 20-plus receptions, 250-plus receiving yards and four-plus receiving touchdowns against a single opponent in a season in the Super Bowl era.
Jason Myers' 27-yard field goal stretched Seattle's lead to 16-7 at half-time, but the Cardinals refused to go away following the interval – Murray's touchdown throws to Dan Arnold and Chase Edmonds, sandwiched in between Carlos Hyde's two-yard run, reducing the deficit to 23-21.
However, the Seahawks were not to be denied as a penalty and Myers' 41-yard field goal saw Seattle improve to 5-0 on home soil in 2020.
