A private nonprofit corporation, funded by anonymous donors, will cover the $400,000 plus an additional $40,000 for memorial's ongoing upkeep.
Each of the dead officers families have given permission for their relative's likeness to be used in the sculpture, according to the city.
Last month, Walker told the city's Cultural Affairs Commission that he anticipates the sculpture could be installed as early as next year.
"We could have some sort of groundbreaking this July 7," he said. "We'll install it next July 7, which will give ample time to do it right."
Walker said that he contacted the city about doing a piece memorializing those killed just after the ambush last July. Since January, he's worked with the Dallas Police Department to find a design that's acceptable to the department and the families of the fallen officers.
"I met with [interim Dallas Police Chief David Pughes] and I met with the police department. I gave them some drawings of other concepts. They didn't care for that," Walker said. "We went back and forth and we came up with this. They approved of this. They loved it and they picked the place they wanted it to be in front of the police department."