Luck, who missed the entire 2017 season while rehabbing his surgically repaired shoulder, was in for two series in the Colts' 19-17 win of Seattle.
Still, the former No. 1 overall draft pick admitted to having more than a few butterflies after finishing 6 of 9 for 64 yards while playing the opening two possessions.
"The first play is always a little nerve-wracking in any game, in a sense, but especially this one," Luck told reporters after the game, per the Indianapolis Star. "After that it sort of slowed down and the rhythm, the flow of the huddle, calling a play, knowing where the play clocks are, getting to the line of scrimmage, showing what your cues are, that operation takes over. For lack of better word, it felt natural."
Although Luck relied on a series of short passes, he did not look tentative, taking a big hit from Seahawks linebacker Bobby Wagner while scrambling for a first down. He also was sacked once.
"I think there was a sense of 'OK, get hit, get up, make sure you're not broken in half on the field,' " Luck said of his short scramble. "It was probably the most excited I have been and will ever be for getting hit."
Luck led Indianapolis to a field goal on his first possession, completing 5 of 7 passes for 55 yards. He sandwiched passes to running backs Marlon Mack and Robert Turbin around an eight-yard completion to T.Y. Hilton.
After starting all 16 games in each of his first three seasons and guiding Indianapolis to identical 11-5 records, Luck was limited to seven starts in 2015. He made 15 starts in 2016, throwing for 4,240 yards and 31 touchdowns versus 13 interceptions.
The Colts finished 4-12 in 2017 with Jacoby Brissett starting 15 games at quarterback. Recurring soreness in Luck's shoulder prompted the Colts to finally shut him down two weeks after he returned to practice in early October. He was placed on injured reserve on Nov. 2.
Appearing in his first game following a layoff of 586 days, Luck said he was trying to prevent himself from getting too amped up. That game plan quickly was discarded.
"Just trying to control my emotions and then I just sort of said 'screw it,'" Luck said of being back in the huddle. "Whatever I want to think and whatever I want to feel, I'm going to feel it and let that happen. It was a little bit of pressure was off, in a sense, and I really had fun. I really enjoyed it.
"I didn't quite know if I would have this much fun practicing football. I didn't know if I would have this much fun again playing football."