Uncle Venner does odd jobs around the Pyncheon Street neighborhood. He also comes every Sunday to visit Clifford, Hepzibah, Phoebe, and Mr. Holgrave in the garden of the House of the Seven Gables. As a young man he was often considered developmentally disabled. The main reason for this assessment? Because he "scarcely [aims] at such success as other men seek" (4.14). In other words, Uncle Venner just isn't interested in material possessions. His complete unselfishness and generosity makes him refreshing and lovable for the gloomy Pyncheons.
Uncle Venner's main obsession is that someday he will retire to a farm. (He's about a million years old now, old enough to call Hepzibah young, so when he plans to do this is unclear.) On this farm, there will be room enough for everyone who needs a place, including Hepzibah and Clifford.
In the last chapter of the novel, Phoebe returns Uncle Venner's generosity by offering him an actual place to go: she suggests that he come live in a cottage on Clifford, Hepzibah, and Phoebe's new country property. Clifford adds, "You are the only philosopher I ever knew of whose wisdom has not a drop of bitter essence at the bottom!" (21.26).
Uncle Venner's good cheer and lack of interest in material things makes him a refreshing contrast to Judge Pyncheon. His happiness, and the love he inspires in other people, underlines Hawthorne's lesson that you can have a better life by not seeking riches.