Donald "Big D" Davenport (played by Hal Sparks) is an inventor, scientist, and father of Adam Davenport, Bree Davenport, and Chase Davenport, and step-father of Leo Dooley. He is one of the main characters of Lab Rats. He and Tasha met each other on an online dating service and married each other.
He is a scientist and inventor that gave chips to Adam, Bree, and Chase, giving them bionic abilities and turning them into superhumans. He actually tried to hide the Lab Rats from Leo and Tasha, but failed to do so, when Leo accidentally found the lair.
He can be full of himself, sometimes boasting about himself. He often doesn't see that Adam, Bree, and Chase just want to be normal teenagers sometimes. He can also be childish and stubborn at times, but he can be very caring and helpful when others are in need of help.