“She is fearless like her mom. She’ll get on any roller coaster that you put in front of her,” Birkhead, told ABC News “20/20” in an exclusive interview. “I could stand right next to my daughter and we could look like twins, and the first thing they’ll say is ... ‘spitting image of the mother.’”
Smith, a reality TV star and former Playboy Playmate of the Year who struggled with prescription drugs, was found dead in a Florida hotel room on Feb. 8, 2007. After an extensive investigation, the official cause of death was ruled an accidental overdose -- Smith had nine different prescription drugs in her system. She was 39. Dannielynn was just 5 months old at the time.
“Anna always wanted a little girl, that was her dream,” Birkhead said. “She went from city to city, as far back [as] the '90s, and she would collect outfits from all these road trips … and hope that one day that she could dress her in all these frilly outfits.”
As their daughter has gotten older, Birkhead, a photographer, said he has tried to explain what happened to her mother.
“The way I've told Dannielynn in the past is that, ‘Your mom took some medicines and she ... might not [have] taken them correctly or the right way, and the doctors couldn't help her, and they tried," he said.
Birkhead had a romantic relationship with Smith but ended up going to court in an epic custody battle for Dannielynn until a paternity test proved Birkhead was the father. Smith's personal attorney, Howard K. Stern, and several other men had also claimed to be the baby's father. The case made international headlines.
But Birkhead said Stern has “been supportive” of him as a father from the moment he won custody of Dannielynn.
“He just said, 'Look, you’ve got to get strong. You’ve got to be there for Dannielynn,'” Birkhead said. “The minute after the paternity test was over ... he’s helping me change Dannielynn’s diaper, [showing me], ‘This is how you feed her,’ … it’s been nonstop since then.”
Birkhead said he's tried to give their daughter a stable life away from the spotlight. The two live just outside of Louisville, Kentucky, but Birkhead said even being thousands of miles away from Hollywood hasn’t stopped all the questions that can come with fame.
“People think [Dannielynn] has got millions and millions of dollars,” he said. “She came home and asked me where the money was, and I said, ‘I’m still looking for it.’”
Attorneys for Smith's estate were locked in a complicated legal battle for nearly 20 years with attorneys for the estate of her late husband, Texas billionaire oil tycoon J. Howard Marshall II.
Smith was just 24 years old when she married Marshall, who was 89 at the time, in 1994. When he died the following year, he left his estate, valued by some estimates to be worth $1.6 billion, to his son, E. Pierce Marshall, and nothing to Smith.
For the next nearly 20 years, Smith’s legal team made numerous attempts to have the courts overturn Marshall’s will and claim money from his estate. The case even made it to the U.S. Supreme Court twice. In 2013, it seemed Dannielynn could inherit as much as $49 million in damages from Marshall’s estate after a California judge’s ruling, but the ruling was later overturned and Dannielynn was denied inheritance from his estate.
“If Dannielynn is to inherit anything via her mom that she was entitled to, so be it, but it’s not like we’re sitting around waiting for one thing to happen,” Birkhead said.
Birkhead said they receive no support from Smith's estate and that he makes a living through photography and flipping houses. The single dad said he is determined to ensure that Dannielynn has a very different life than her mom.
“It’s just like any other kid who has lost a celebrity parent. They think that the child is automatically destined for the same path,” he said. “[But] she can work me like her mom could work people. She gets what she wants.”