Dannielynn looked beautiful in a high-low, bright yellow dress with pink flower details and a bow around her waist as her dad matched her outfit with a pink tie and pocket square.
The extravagant night took place at Patricia Barnstable Brown's Louisville home. The father-daughter duo has made a tradition of going to the Derby every year. They have attended since 2010, topping their outfits every year.
Birkhead took to social media to post about the special outing.
"Headed to the 31st annual Barnstable-Brown Derby Eve Gala with Dannielynn, in her awesome dress by Junona. The start to an awesome weekend! #proudpapa," he captioned the photo on Twitter.
Other guests included "That 70s Show" heartthrob Wilmer Valderrama, "Real Housewives of Dallas" star Cary Deuber, and "Bachelor" couple Kendall Long and Joe Amabile.
Dannielynn had a turbulent early childhood. After her mother died in 2007 of a drug overdose at age 39, her father's identity was uncertain until Birkhead took a DNA test that confirmed paternity.
Smith had claimed her boyfriend, Howard K. Stern, was Dannielynn's father.
Dannielynn was just a year old when her mother died, which came after the passing of her 20-year-old brother, Daniel Wayne Smith, the year prior.