Looking right at the camera, Saylor appears happy and healthy in a cozy white shirt, baby pink headband and arrow-patterned pants.
"Here is my little angel, Saylor," Cavallari captioned the snap. "I couldn't have asked for a better baby. We're very lucky to have such a sweet, easy girl, especially since she's the third one! I guess there was no other option! Happy new year, everyone!"
Although this is the first full-length shot we've seen of Saylor, the 29-year-old -- who is also mom to sons Camden Jack, 3, and Jaxon Wyatt, 1 -- has been teasing her followers with glimpses of her daughter for weeks.
On Christmas, she shared an adorable pic of her holding Saylor, dressed in a holiday-themed onesie, up in the air. "Saylor's first Christmas!" she captioned it, with the hashtags "#MerryChristmas" and "#ChristmasJammiesOnPoint."
Last month, Cavallari's brother, Michael, was found dead in Grand County, Utah, after being reported missing for nearly two weeks. In the midst of her family tragedy, she said she's taking comfort in her "little angel."
"She has been my light throughout this whole thing and has given me so much strength," Cavallai wrote on Instagram, referring to Saylor. "Thank you baby girl for coming when u did." Hear more in the video below.