[3] She is the daughter of Margaret (née Chessington), a California-born teacher, and Arnold Leo III, an editor at Grove Press, fisherman, and former spokesman for the East Hampton Baymen's Association.

Leo appeared in a supporting role alongside Sean Penn, Naomi Watts, Benicio del Toro, and Clea DuVall.

In 2006, she won the Bronze Wrangler at the Western Heritage Awards for Outstanding Theatrical Motion Picture for The Three Burials of Melquiades Estrada shared with Tommy Lee Jones who also produced the film.

I was struck by how intensely determined she was to make the payments, support her two children, carry on after her abandonment by a gambling husband, and still maintain rules and goals around the house.

Leo appeared in a series of films throughout 2009, including According to Greta, the title character in Stephanie's Image, True Adolescents, and Veronika Decides to Die.

Rick Bentley of The Charlotte Observer said: "Both actors (Mark Wahlberg and Christian Bale) are very good, but they get blown off the screen by Melissa Leo, who plays their mother, Alice Ward.

[13][14] Prior to her win, Leo had created some controversy by attempting to self-promote her Oscar campaign, rather than rely on the marketing department of the studio.

Leo personally bought ad space in Hollywood trade publications, which was initially thought might backfire in a similar manner to previous Oscar contenders Chill Wills and Margaret Avery.

[15] Following her Oscar win, Leo appeared in the HBO miniseries Mildred Pierce alongside Kate Winslet, Evan Rachel Wood and Guy Pearce.

Her next projects include the satirical horror film Red State, the independent comedy Predisposed with Jesse Eisenberg currently in pre-production[16] and the crime thriller The Dead Circus based on the novel by John Kaye with Michael C. Hall and James Marsden currently in development.

Leo appeared in the action-thriller Olympus Has Fallen as Ruth McMillan, the Secretary of Defense who was held hostage by terrorists in the White House; and Oblivion as the main antagonist Sally.

[1] Leo then moved to Stone Ridge, New York, where a 200-year-old farmhouse was her permanent residence for three decades, though she often traveled and lived elsewhere temporarily for work.