Last October little Serafina Murphy, who was only 22 months old at the time, underwent surgery at the Lurie Children's Hospital to fix a hole in her heart.
His wife took pictures of Serafina in the hospital and they quickly went viral.
As a way of thanking his daughter's surgical team, Sean Murphy will be running in Sunday's race.
"I joined the Lurie's marathon team to help raise these funds to give back to the hospital that, again, gave my daughter her life," Murphy said.
Murphy asked those who shared the picture of his daughter on the web, to donate money to his marathon goal.
Friday he is only $600 short of his $5,000 goal.