The wing-back headed the only goal of the Betfred Cup final to give Callum Davidson's team a 1-0 victory over Livingston and secure the club's second trophy triumph.
But his first thought as the final whistle blew was of his mother Elizabeth, who died from cancer back in 2019 just two days short of her 25th wedding anniversary.
He told Premier Sports: "I'm over the moon. I can't hide the emotion. I'm still buzzing.
"I want to thank my mum. Obviously she has passed away but this is massive for my whole family.
"I think everyone in the family will have a tear in their eye but I'm absolutely buzzing.
"This is the second trophy in the club's history and absolutely massive for everyone in Perth.
"I expect they will be partying on long into the night.
"I don't know if we will be able to enjoy it ourselves. We're meant to be in training tomorrow - hopefully we'll get the day off."
Rooney found himself facing a surprise battle with Livi captain Marvin Bartley, who was shifted out from the centre of midfield in a bid to thwart his threat down the right wing.
The 24-year-old added: "The tussle with Marvin was probably my hardest of the season to be fair.
"He does the dirty work well, he's always grabbing you and trying to wind you up. He's got a wee bit of pace about him as well.
"But I'm just so happy to win the battle."