The two stars will be among those performing and speaking at a rally in New York's Beacon Theatre on Friday (14Dec12) and they're hoping their efforts will persuade U.S. leader President Barack Obama to release the 68 year old.
Obama has only used his ultimate power to pardon one person since he was first elected president in 2008.
Common and Browne will be joined at the star-studded rally by folk legend Pete Seeger, filmmaker Michael Moore, actors Danny Glover and Peter Coyote and Harry Belafonte, who will host the event.
Peltier, who has been listed as a political prisoner by human rights group Amnesty International, was arrested in 1976 and charged with the murder of two undercover Fbi agents during a 1975 shoot-out on the Pine Ridge Indian Reservation in South Dakota.
He was sentenced to two life terms behind bars even though no witness identified Peltier as the shooter at the trial.
Common tells Rolling Stone magazine, "We're hoping that Leonard will receive the freedom that he deserves, and obviously it would be great if our president can help participate in that. I have to speak up, and I feel like being an activist means also not only speaking, but being active and standing up for the struggle, and standing up for those who are being served with injustice."
Coyote, who has befriended Peltier in recent years, adds, "He's the Nelson Mandela of the Native American movement, and he's a friend of mine.
"We have millions of people from around the world that are looking at the United States as a beacon of human rights, and we've held this one, ageing Native American, who even the government says, 'We have no idea what Mr. Peltier's involvement was.' And it's a shame on our national honour."
Peltier is currently scheduled for release in 2040.
Friday's event will benefit the Leonard Peltier Defense Offense Committee.