Appearing on E! News Live, a choked-up Voight said he hadn't spoken to his daughter in months and that their relationship had seriously deteriorated since shooting Tomb Raider together in fall 2000.
"I've had difficulty reaching her," Voight said.
Voight said the last time he saw her was during Paramount's 90th anniversary party earlier this year. "I ran to give her a hug, and one of her representatives stepped in my way and said, 'Get back,' " Voight recounted.
"She's been staying away from me because she knows I've been trying to reach her to get help."
Voight did not specify exactly what sort of help he was seeking for his daughter, only that she has been suffering from "serious emotional problems that I have witnessed very closely."
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> The 27-year-old Jolie has admitted to cutting herself (she has scars from self-inflicted knife wounds) and nearly having a breakdown on the eve of her marriage to Thornton two years ago.
In a statement released to Access Hollywood, Jolie said, "I don't want to make public the reasons for my bad relationship with my father. I will only say that like every child, [her brother, Jamie] and I would have loved to have had a warm and loving relationship with our dad.
"After all these years, I have determined that it is not healthy for me to be around my father, especially now that I am responsible for my own child."
Voight, 63, said the difficult relationship with his daughter dated back to her youth. The actor, an Oscar winner for Coming Home, divorced Jolie's mother, Marcheline Bertrand, when Angelina was still an infant.
Still, said Voight, "I've always been there for my kids, always been there for the family."
He and Jolie temporarily reconciled to make Tomb Raider, in which he briefly appears as her onscreen father. The actor termed the experience "one of the happier moments of my life." (Their heartfelt post-scene embrace is captured on the Tomb Raider DVD.)
But Voight didn't exactly win points with Jolie earlier this year, when, during an Oscar nominees luncheon in March, he blurted out that he had become a grandfather and that Jolie and Thornton had adopted a baby boy.
The couple later confirmed they had taken custody of a Cambodian boy, but said they were "surprised" about Voight's announcement. The couple didn't want to publicize the adoption until it had been finalized by U.S. and Cambodian officials.
On Thursday, Voight said he still hasn't met his grandchild, Maddox. "It's a great pain that I haven't been able to see the baby."
Jolie is currently training for Tomb Raider 2, which begins shooting in three weeks. She filed for divorce from Thornton on July 17, citing irreconcilable differences. The actress, Oscar'd for Girl, Interrupted, claimed she hadn't seen or spoken to him since early June.
Voight said it's been even longer since he had a heart-to-heart with her, and that's why he's going on television to try and reach her.
"The reason for my plea is not for myself," he told E! "I want nothing more than to hold my baby in my arms.
"I want to tell Angie that I love her and I want her to get the help she needs...And I want her to find true love."