The German spent more than four years in the same role at Bundesliga side Wolfsburg before leaving at the start of the year. He has held similar positions at Cologne, Hannover and Alemannia Aachen.
Schmadtke will begin his new role at Liverpool on July 1st and replace Julian Ward, who is leaving after 12 months in the position and more than a decade at Anfield.
"Jorg will work with our football operations department as it continues to provide support for Jurgen Klopp (55), in keeping with our ongoing endeavour to keep growing and developing the club in all areas," Mike Gordon, the president of Liverpool's owners, Fenway Sports Group, said in a statement.
"We must also bid a fond farewell to Julian Ward, who has served us with unstinting diligence, fortitude and energy in a number of roles."
Liverpool finished fifth in the Premier League, outside the Champions League qualification spots for the first time since 2016-17.
