The Norwegian, who was part of the Rovers team that lifted the Premier League trophy in 1995, has been handed a three-year deal.
And despite previously criticising the Venky's regime at Ewood Park, the 43-year-old says he was convinced during talks with the club's owners that they share his ambitions to get Rovers back in the top flight.
"It is fantastic to be here, I had a good feeling driving back into the town," Berg told the club's official website. "I'm really looking forward to it.
"We want to win promotion; that is our own ambition, it doesn't matter if it is directly or via the play-offs, we only want promotion.
"I've spoken to the people inside the club, I know their ambitions, I know what they are planning. The owners have made very important steps to take the club forward once again.
"I think the most important thing is to continue what we have started. We want to build on the results, keep being defensive but creative."
Berg also said he would not be making any immediate changes to the personnel at Ewood Park.
"The backroom staff have done well, it would be foolish for me to come in here and start making changes before i know anyone personally," he said.
"I will assess how we will work together, to see if we have the same ideas. I'm looking to work with the people we have here."