Born in Maracaibo, Venezuela, Guillermo Cuellar studied ceramics at Cornell College, Mt. Vernon, Iowa, where he earned a BA in Art. After working as an environmentalist, he returned to pottery in 1980. In 1986, Cuellar set up a studio in the village of Turgua, Venezuela, an hour southeast of the capital city, Caracas, where he made pots for the following 18 years. In 1981, he worked as an assistant to Warren MacKenzie, who was teaching in Caracas. Subsequently, Cuellar regularly shared studio experience with MacKenzie in Stillwater, Minnesota, from 1984 to 2006. In 2005, Cuellar and his wife, Laurie MacGregor, and children, Carlos and Alana, established a home, studio, and showroom near Shafer, Minnesota, where he currently makes pots. Cuellar participates as one of seven host-studios on the Minnesota Potters of the Upper St. Croix Valley Annual Pottery Tour.