His work has been shown all over the world, including at the National Museum of Natural History in Stockholm, Sweden; the Salon d'Automne in Paris, France; the National Gallery  

in Botswana, Africa; the Exhibition Hall, Beijing, China; the Guildhall in London, U.K.; the National Geographic Society, Washington, D. C.; etc.

Kent has completed and installed a large number of monumental sculptures worldwide, including "Deinonychus Dinosaurs", a 25ft monument on Logan Square, Philadelphia; "American Eagle" monument, a 21ft composition in Princeton, NJ; a Conservation Fountain for Washington, D. C.; The Broward Convention Center Marine Fountain, 150ft long, by 36ft tall for the City of Ft. Lauderdale, Fl.; and a 65ft tall installation for the Swedish Government Tele-Com Center in Stockholm, Sweden. His latest monument is the gigantic "Spirit of Nebraska’s Wilderness" fountain in Omaha, Nebraska, which comprises 58 over-life size Canada Geese in bronze and stainless steel.

Ullberg is a member of numerous prestigious art organizations from which he has received many outstanding awards, i.e. the National Academy, N.Y.C.; the National Sculpture Society, N.Y.C.; National Academy of Western Art, Oklahoma City, OK; Society of Animal Artists, N.Y.C.; Allied Artists of America, N.Y.C.; the American Society of Marine Artists, Ct.; the National Arts Club, N.Y.C.; the Society for Wildlife Art of the Nations, Sandhurst, England.