Larry Birkhead Reflects on Relationship with Anna Nicole Smith, What She Was Really Like in Private

Larry Birkhead, who dated the late model and actress Anna Nicole Smith and is the father of their daughter, Dannielynn, is opening up about their romantic but tumultuous relationship and how Smith changed his life.

“The thing about Anna was … it was almost like a split personality,” Birkhead told ABC News “20/20.” “Because when the camera was going, she was a whole different thing … that was more, to me, an act than it was the real person, who she was.”

Watch the full story on ABC News “20/20” THIS FRIDAY, Feb. 10 at 10 p.m. ET

Larry Birkhead is pictured here with ABC’s Deborah Roberts during an interview with ABC News “20/20.”

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 when her mother died. Now at age 10, Birkhead said Dannielynn reminds him of Smith more and more every day, but he’s determined to ensure their daughter takes a different path from her mother’s.

Smith was born as Vicki Lynn Hogan in the small town of Mexia, Texas. She dropped out of high school at age 15 and worked full-time at a local fast food chicken restaurant.

When Smith talked about her childhood, Birkhead said they “were not the happiest of stories.”

“[She was] poor, abused,” he said.

Smith’s first marriage collapsed after a year, leaving her broke and raising her baby boy Daniel on her own. To make ends meet she took a job stripping at a gentleman’s club in Houston, where she met J. Howard Marshall, a Texas billionaire oil tycoon.

In 1992, Smith got a big break when she was chosen to be a Playboy centerfold. She would go on to become Playmate of the Year and become the face of a famous Guess Jeans ad campaign. She even had small roles in several films, including “Hudsucker Proxy” and “Naked Gun 33 1/3.”

“She was living the dream,” Birkhead said. “Here she is, a little girl from Texas, went from working in a chicken shack to making movies with big stars in Hollywood.”

Smith was just 24 years old when she married Marshall, who was 89 at the time, in 1994. By some estimates, Marshall spent upward of $12 million showering his new bride with gifts, and many accused Smith of being a gold digger. But Birkhead said she loved Marshall.

“That was no act,” he said. “She genuinely has some kind of a deep love for him. Now, I don’t know if it was the kind of, you know, physical type of thing, but it was what he did for her and what he did for Daniel and that he changed her life.”

Smith told ABC News in a 2000 interview that Marshall “took me out of a terrible place and he cares for me and my son, and in return, I took care of him, and I loved him for that.”

But when Marshall died in 1995, just 14 months after their wedding day, 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.

By 2002, Smith’s journey from being a stripper to being at the center of a national legal showdown became ripe fodder for a burgeoning industry — reality TV. She, her then-teenage son Daniel and her longtime friend and personal attorney Howard K. Stern and many others appeared on “The Anna Nicole Show” on E! Entertainment.

ARCHIVAL VIDEO: Anna Nicole Smith Talks About Her Reality Show