The Blues opted for Nick Graham as their substitute against Gold Coast at Etihad Stadium, and a calf injury to Chris Yarran meant he was injected into the game early, clearing the way for Sheehan to play four quarters.
The 23-year-old did his best work across half-forward, finishing with 13 possessions and five inside-50s.
"It was brilliant, quite overwhelming," Sheehan, who first trained with Carlton for four weeks back in 2009, told afl.com.au.
"It's great to run out with all the lads after training with them all year, and to play alongside the likes of Marc Murphy and Chris Judd is a great honour for me.
"It was great to get a full run out to see where you're at in terms of the pace of the game and your fitness, so I was quite happy to get the full game."
Sheehan decided not to pursue an AFL career back in 2009 but he generated renewed interest after an outstanding International Rules Series last year.
The Corkman was told on Tuesday he would debut, giving his Mum enough time to make the trip from Ireland.
"She was well able to make the trip and she really wanted to see it, it's a one off thing," he said.
Ciaran Sheehan with mother Liz who flew in from Ireland for her son's debut. Picture: AFL Media
"My girlfriend Amy at home, who was out with me from the start, she didn't get the opportunity to come out, she has exams.
"She's been with me all the way so I owe an awful lot to her.
"I think a lot of friends and family back home all tuned in, so it was great to have their support even from back home."
Sheehan impressed with his penetrating kicking on Saturday and he barely wasted a possession.
Used at both ends of the ground in 14 VFL games for the Northern Blues this season, he said the skills of Australian football had been the easiest aspect of the game to pick up.
"That's what me and Zach (Tuohy) always talk about ... understanding the structures and how the game is played is the harder part," he said.
"Using the ball well is an important part of our game back home so we just trained and trained and it came off OK today."
Malthouse was clearly thrilled when he sought Sheehan out in the rooms post-match to congratulate him, saying the Blues had found another player.
"I'm pleased for him. His mum got over last night, I'm pleased for her," the coach said.
"And I'm pleased for Zach, because they both came over together five or six years ago.
"Their paths have been in different directions and they've come back.
"It's terrific, because it gives us another player."
"My girlfriend Amy at home, who was out with me from the start, she didn't get the opportunity to come out, she has exams.
"She's been with me all the way so I owe an awful lot to her.
"I think a lot of friends and family back home all tuned in, so it was great to have their support even from back home."
Sheehan impressed with his penetrating kicking on Saturday and he barely wasted a possession.
Used at both ends of the ground in 14 VFL games for the Northern Blues this season, he said the skills of Australian football had been the easiest aspect of the game to pick up.
"That's what me and Zach (Tuohy) always talk about ... understanding the structures and how the game is played is the harder part," he said.
"Using the ball well is an important part of our game back home so we just trained and trained and it came off OK today."
Malthouse was clearly thrilled when he sought Sheehan out in the rooms post-match to congratulate him, saying the Blues had found another player.
"I'm pleased for him. His mum got over last night, I'm pleased for her," the coach said.
"And I'm pleased for Zach, because they both came over together five or six years ago.
"Their paths have been in different directions and they've come back.
"It's terrific, because it gives us another player."
Ciaran Sheehan says the skills of Australian football aren't that hard to pick up - you be the judge.
