Amy Palmer, 33, from Pennsylvania, explained that her husband Andre Palmer had worked his third night shift in a row.
“This is a picture of a hard working man dedicated to his family,” she wrote on Facebook.
“He’s right here with his son who is in the hospital. He’s so tired but he’s here!
“Father of the year award goes to Andre Palmer. I love you more than words baby.”
Palmer explained her 20-month-old son AJ had been admitted to hospital after suffering a bad asthma attack.
Her husband works from 11pm until 7am every night, and she hadn’t expected him to come to the hospital after work.
“I expected him to go straight home,” the mum told PEOPLE.
“He was exhausted, but he’s such a good dad – so he came straight over to see his son.”
Palmer said she had fallen asleep on the only chair in the room and woke up at 8am to see her husband asleep under the crib.
“He would do anything for his kids,” she added. “I just had to take a picture of it.”
Palmer’s Facebook post was shared 1,200 times within three days of being uploaded on 5 July and had nearly 9,000 likes.
She posted a follow-up status on Facebook thanking everyone for their support and well wishes for her son.
“I am so overwhelmed with so much emotion right now,” the mum wrote on 7 July.
“I just want to take a minute to thank everyone who reached out to us whether by sharing the story, commenting, or sending messages.
“I appreciate all of the prayers and thoughts. I took the picture because I thought what a selfless thing for my husband to do.
“He could have went home after work, he could have asked me to get up. I would have never imagined that it would have touched so many people.”
Palmer said her son was doing “much better” and was at home resting.