Conor's post quickly caught the attention of fans.
"Omgosh absolutely gorgeous little girl looking at her daddy," one fan penned.
"Yay! So happy for you and the family," said another.
Several of Conor and Mary's Bachelor in Paradise co-stars also gushed over baby Summer in the comments.
"My heart," penned Renee Barrett.
"YAY! She’s so beautiful," exclaimed fellow finalist Alisha Aitken-Radburn.
Just days before Summer came home, Conor thanked fans for their support via Instagram, explaining that the new arrival had to stay in hospital a little longer than normal.
"Thank you for all the amazing messages guys!" he captioned a photo of the sleeping bub.
"Summer is still in hospital until she puts on some more weight but is relaxed and living her best life. She should be home soon."
Earlier this month, Conor treated his partner Mary to a very lavish selection of push presents.
In a video uploaded to Instagram, a blindfolded Mary was gifted a pair of Louis Vuitton sandals, a large handbag with the iconic brown and bronze LV logo, and a zip-up pouch purse.
"My baby daddy @conorjcanning gave me an amazing push present. Even though I didn’t push the baby because I had a c-section, I still deserve it," Mary joked in her caption.
Summer is Mary's second child - the Bachelor star is also a proud mum to seven-year-old daughter Chanel from a previous relationship.