Kenny, who replaces Jon Daly as St Pat’s boss, has a wealth of League of Ireland management experience, having started with Longford Town at the age of 26.
He has also managed Bohemians, Derry City, Shamrock Rovers, Dundalk and Scottish side Dunfermline.
“It’s been a bit of a whirlwind, I’m looking forward to getting started, it’s a new chapter in my life and a new chapter for the club, and I’ll be giving it everything,” said Kenny.
“Garrett Kelleher [chairman] has shared his vision for the club with me for a long time, he has plans for the Stadium, to expand the club into America, European progression and a lot of exciting plans really.
“The reason I signed a longer contract is the build the club over a period of time and I’m looking forward to driving it forward.”