Police say King Hill was last seen at 9:50 a.m. at 31st and Page streets in Strawberry Mansion.
During a news conference on Monday afternoon, Capt. Mark Burgmann said the police department is working tirelessly to bring the child home.
"We've put a tremendous amount of resources to this, probably more resources than we've ever devoted to any other investigation I've had here in the past over 40 years," he said.
The toddler is described as three feet tall and weighing 32 pounds with a thin build, light brown complexion, with brown eyes and black hair.
The toddler's grandmother, Kimberly Hill, told Action News that King's stepfather had the boy since the end of May.
The stepfather was to drop King off at the mom's house in two weeks for the toddler's birthday.
Instead, the mom received a text from the stepfather that set off the search for her son. The stepfather said a babysitter had dropped off King.
"She gets a text saying, 'Did you get the baby? She dropped him off at 33rd and Diamond.' That's the first time we heard of this babysitter. I don't know who this woman is," Kimberly Hill said.
MISSING: family sent me this video of 2 year old King Hill, missing since Tuesday at 31st and Page in Strawberry Mansion. Police have not released any suspect information @6abc pic.twitter.com/ILKxpD863d— Jaclyn Lee (@JaclynLeeTV) July 9, 2020
The grandmother says she does not believe the stepfather had anything to do with King's disappearance.
Burgmann said authorities are determined to figure out what happened to King.
"We're leaving no stone unturned here. We're not going to stop until the child returns," he said.
Burgmann said that they've been able to talk to everyone involved, including the parents and the babysitter. Everyone was cooperative, police say, but they still have no new leads.
"Anybody who maybe had prior contact, please contact us. No matter how insignificant it is, so we can follow up on it," he said.
Anyone with any information on King's whereabouts is asked to contact Special Victims Unit at 215-686-3251 or 911.