The deal adds a catalogue of more than two million songs -- including some of the greatest hits from the 20th century -- to Sony's already huge repertoire.
The agreement is Sony's first major deal under new CEO Kenichiro Yoshida, who noted the music business has enjoyed a "resurgence" in recent years due to streaming services provided by companies such as Spotify and Apple.
With this purchase, Sony "is becoming one of the biggest music publishing companies, both in name and reality", Yoshida told reporters.
"We are thrilled to bring EMI Music Publishing into the Sony family and maintain our number one position in the music publishing industry," Yoshida said in an earlier statement.
"I believe this acquisition will be a particularly significant milestone for our long-term growth," added Yoshida, who took the Sony helm last month.
Sony said it had signed a deal with Abu Dhabi-based investment firm Mubadala to buy its 60 percent holding, giving the Japanese firm a stake of about 90 percent.
The agreement values EMI Music Publishing at $4.75 billion, the Sony statement said, adding that "the closing of the transaction is subject to certain closing conditions, including regulatory approvals".
Yoshida also Tuesday unveiled Sony's latest strategic plan, which aims to bolster its content business -- pursuing the direction his predecessor Kazuo Hirai had taken to revitalise one of Japan's best-known firms.
"We are a technology firm, but the technology means not only electronics but also entertainment and content-creation" in today's world, Yoshida said.
Sony will continue to build up its content services -- as shown by Tuesday's deal -- and also invest heavily in cutting-edge technologies including image sensors, he said.
