Alexander, who only retired from playing this summer, takes on the role with Preston chairman Peter Risdale overseeing substantial cost-cutting at the club.
"A successful youth development programme can have major benefits for a football club and for us to continue to invest in the programme it is essential that the strategic objectives of the first team and youth team management are strictly aligned," he said.
"Graham’s experience, not just with us, puts him in a unique position to ensure that our investment in our youth programmes will be optimised in the coming years."
Alexander will replace Dean Ramsdale and Jamie Hoyland, who were previously part of the club's youth structure.
Ridsdale said there were "a small number of job losses" at the club as part of a "fundamental review of our off field organisation structure".