Bush said he was inspired to take up painting after reading a Winston Churchill essay, and when he hired an instructor, he told her, "There's a Rembrandt trapped in this body. Your job is to find it."
The 43rd president showed Leno paintings of his dog Barney and a stray cat that he adopted and named Bob. He even brought out a portrait of Leno.
"I can't make fun of him now," Leno said jokingly as he received his painting.
The 67-year-old Bush has kept a low profile since exiting office in 2009 while the country was in two wars and struggling with an economic crisis.
"It's hard for some to believe, but I think eight years in the spotlight's enough," he said.
Former First Lady Laura Bush also appeared on Leno's couch to discuss the couple's charitable causes. They also showed the strand of pearls Bush gave her for their 36th wedding anniversary and a video clip of their first grandchild, nicknamed Mila.