The former striker won the 1990 World Cup and earned 90 caps for Germany before coaching the side between 2000 and 2004, helping them reach the 2002 World Cup final.
He has come out of retirement to take his current post at a difficult time following the departure of Oliver Bierhoff after Germany's first-round World Cup exit in Qatar in December.
Voller's biggest goal is to help prepare the team for a successful Euro 2024 on home soil, he said, and getting the supporters back behind the national side.
"It is a bit a of a deja vu for me but not really the same. Formerly as a coach and now as national team director," Voller told a news conference.
"We need to bring the fans who have long supported us for years," Voller said. "Even before Qatar you could sense there was something that was broken."
Four-time world champions Germany also crashed out of the 2018 World Cup in the first round while failing to advance past the round of 16 in last year's Euros.
"Then came the disaster of Qatar. We certainly played no good role there," Voller said.
"But we have to leave it behind us and now win back those fans. That will only come through good performances. We have a big tournament on home soil in 18 months."
Germany will host Euro 2024 from June 14 - July 14 across 10 cities.
For German Football Association (DFB) President Bernd Neuendorf, getting Voeller on board ahead of the Euros was crucial for the team's success in front of the home fans.
"We needed someone to take over the responsibility," said Neuendorf. "He (Voller) is now in charge of the sporting side only for the national team and the Under-21s. An absolute focus and concentration on this tournament (Euro 2024)."
