A native of Sweden, Ullberg is recognized as one of world's foremost wildlife sculptors. He studied at the Swedish University College of Art in Stockholm. He also worked at museums in Germany, the Netherlands and France. He was curator at the Botswana National Museum and Gallery and in the U.S. at the Denver Museum of Nature and Science. He has made his home permanently in the United States where he now lives on Padre Island, Corpus Christi, TX. He also maintains a studio in Loveland, Colorado. In 1993 and once again most recently in 2008, Ullberg received the Henry Hering Medal from the National Sculpture Society (NSS) for outstanding collaboration between patron, architect and sculptor for his monumental sculptures. In 2015, he received NSS' Sculpture House Annual Award.