"He raised $300 all on his own. He just sat there with his little bin and people put money in," Ms Randle said.
Ms Randle puts part of Harry's success down to the sign. "People would come up and read his sign and realise he was part of the show," she said.
Ms Randle said SPCA staff were surprised to receive the donation. "They were really amazed because it was quite a lot of money for one dog."
She said Harry may fundraise at the next air show and donate his efforts to another charity.
Wairarapa SPCA centre manager Val Ball said the SPCA were extremely grateful for the donation. "We want to say thank you to Harry and to Sara for the inventive way in which they did what they did. That's the first money we've had raised by a dog, it was just great."
Harry's money will go towards renovations to the SPCA's puppy room.