Wallace is an inveterate inventor, creating elaborate contraptions that often do not work wholly as intended. Their appearance is similar to the illustrations of W. Heath Robinson and Rube Goldberg, where Nick Park has said of Wallace that all his inventions are designed around the principle of using a "sledge-hammer to crack a nut". Some of Wallace's contraptions are based on real-life inventions. For example, his method of waking up in the morning uses a bed that tips up to wake up its owner, an invention that was exhibited at the Great Exhibition of 1851 by Theophilus Carter.
Wallace has had three romantic interests. The first was wool shop owner Wendolene Ramsbottom, which ended quickly when Wendolene told Wallace that she was allergic to some cheese. The second was Lady Campanula Tottington in The Curse of the Were-Rabbit, whom Wallace fondly calls "Totty". In A Matter of Loaf & Death, Wallace becomes engaged to Piella Bakewell, who turns out to be a serial killer of bakers.
