They adopted Ana from Siberia, Alex from South Korea, and, in 2010, Emma from China. Those who know them have joked that they are the "Brad and Angelina of little people" -- not only because of their international adoptions, but also because of how much they embrace each child's heritage.
In addition to advocating for little people, the Johnstons are big advocates for adoption. They are quick to point out that they did three overseas adoptions without taking out any loans. They relied on various grants to make it work financially.
How do they support all the kids? "We live within our means," Trent Johnston said. "We try to do everything ourselves." Although dwarfism is considered a disability, the Johnstons don't collect any disability payments.
"I do believe there are little people that are truly disabled," Amber said. "But our family is not."
Size hardly limits Amber Johnston, a stay-at-home mom who also heads the local Parent-Teacher Association and Girl Scouts. Trent Johnston is a hands-on dad -- literally. He crafts pedal extensions for cars to help dwarfs drive. His main job is as the grounds supervisor at a local college.
One sizable obstacle they face is the stares they get. Jonah, the eldest son, said, "It's frustrating more than sad. I don't think they would want us to stare at them."
When Elizabeth was in third grade, bullies called her a midget. Her answer? "That's how God made me -- that's how he loves me."
Supported by faith and family, the Johnstons have realized their dream and are making it work. When asked what they most want people to know about them, Jonah said, "we're no different than other people. It's just our height difference."
Watch the full story on "20/20" Friday at 10 p.m. ET.