Ghanaian striker Collin Quaner will work under Jan Siewert at English Premier League side Huddersfield Town.
Siewert replaces David Wagner, who left the club by mutual consent last week with Town rooted to the bottom of the league table.
"Huddersfield Town is delighted to announce the appointment of Jan Siewert as its new head coach," said chairman Dean Hoyle on the club's website.
“I’d like to begin by officially welcoming Jan to Huddersfield Town. I’m tremendously excited about working with him as our new Head Coach.
“Let me start by addressing the obvious. We enjoyed tremendous success under our previous Head Coach, David Wagner, and we’ve subsequently appointed a new Head Coach that bears many similarities to him; a young, aspirational German from Borussia Dortmund II.
“However, that does a disservice to Jan, who is his own man. There is much more to this appointment than that."
Wagner guided Huddersfield into the top flight in 2016-17 for the first time in 45 years after winning the Championship playoff final against Reading. With the odds stacked against him, he then kept them in the top flight last season.
Siewert has previously coached Germany's international youth sides and held senior management roles at VfL Bochum and Rot-Weiss Essen apart from his role in charge of Dortmund's reserves.
Quaner is having a season to forget after spending large chunk of the campaign of the treatment table.
He has made just one appearance all season after returning from injury last month.