The Beatles star, along with Pamela Stephenson, called for India's forest minister Dr Patangrao Kadam to help release the animal.
The 13-year-old, named Sunder, will be rescued from his shed in the Maharashtra district and moved to a wildlife centre, The Sun reports.
McCartney had previously written: "I have seen photographs of young Sunder, the elephant kept alone in a shed at a temple and put in chains with spikes.
"Years of his life have been ruined by keeping him and abusing him in this way. Enough is enough. Get Sunder out."
Mimi Bekhechi of PETA said yesterday: "We are grateful to the forest minister for agreeing to liberate Sunder."