Crowd favourite Sirakov is the club's all-time leading scorer with 206 goals between 1981 and 1994. He won five league titles and four Bulgarian Cups with Levski as a player.
"I'm excited because I grew up here and I achieved everything with Levski," the 51-year-old, who was part of Bulgaria team who reached the 1994 World Cup semi-finals in the United States, said.
"But at the same time, I realise it's a huge responsibility."
During Sirakov's previous spell as Levski's sporting director, The Blues, who have not won a trophy since 2009, reached the UEFA Cup quarter-finals and played in the Champions League's group stages.
Former captain Hristo Yovov, who announced his retirement last month, was named as Levski's technical director.
"I hope that these two figures will help our club win the title and the Cup next year when we'll mark our 100th anniversary," said Levski president Todor Batkov.
- Sports & Recreation