Mr. Dudley is a lovable old fraud who conned his way into the Marvel Family. He is not a blood relative but rather the adopted uncle of the three kids. Dudley has no super-powers to speak of, but does change into a makeshift version of the Marvel Family uniform when danger strikes -- often during a real lightning strike brought down by one of the other mebers of the family during a transformation. Dudley often covered for his lack of powers by claiming his Shazambago was acting up. This ruse never fooled Billy, Freddy, or Mary but they went along with his charade.

Dudley was often seen in the company of Mary Marvel, he was kind of a guardian to her while she was on an adventure. Dudley also participated in many Marvel Family adventures. He founded Shazam, Inc., a charitable organization that allowed the common man to access the Marvel Family for help. This organization was often the catalyst for many Marvel Family adventures.

Although powerless, Dudley often saved the day with his quick wit. It was Uncle Marvel who tricked the evil Black Adam into saying Shazam's name which caused Adam to turn back into the mortal Teth-Adam.

With a threat from Sivana to destroy major American cities from coast-to-coast, Shazam charged the Marvel Family with stopping the evil scientist whenever he appeared. Station WHIZ president Sterling Morris charged Billy Batson with the job of covering the story with Dudley as Billy's driver and aide-de-camp. The daring pair went on the road together and traveled across the country visiting major cities battling and capturing their dastardly enemies whereever possible.

Dudley was briefly portrayed as Billy's real uncle in a series of stories that took place in an alternate reality. Dudley's profession was that of stage magician for hire. In that same set of stories, the evil Dr. Sivana was also Billy's uncle but through marriage.

Sivana tried to steal Billy away from Dudley in a custody battle to gain access to the fortune left his nephew from Billy's parents' death. Sivana's evil genius was also instrumental in reviving the nefarious Black Adam. Dudley and Billy were eventually reunited once Sivana's evil scheme was discovered. Billy and Dudley lived together in an apartment in San Francisco with Billy pulling in the bulk of the rent from his job as a broadcaster at Station K-WHIZ. Dudley never donned his Marvel guise in these stories.

Perhaps the saddest chapter in Dudley's life was when he allowed his emotions to consume him when confronted by the evil Mr. Finish. Finish threatened to kill Dudley if he didn't think up seven people that the evil pooka could kill in his place. Although he knew he couldn't accept Finish's deal, a drunken Dudley, still though of seven people: Mrs. Wormwood, Delroy Amberson, Ebenezer Batson, Bobby Napoli, Dudley's ex-wife Audrey, her husband Morty and Mary Bromfield. It was Mary's inclusion of Dudley's list that nearly drove a wedge between Captain Marvel and his friend. Cap was able to defeat the evil Mr. Finish by using a magical ring of King Solomon's that could banish demons.