[1] Moeller was born in New Holstein, Wisconsin, but moved to Milwaukee at a young age.
As a teen Moeller attended the Milwaukee Art Students’ League with young artists such as Edward Steichen.
Gustave then took classes at the Chicago Art Institute while working as a commercial engraver.
Moeller also attended the Academy of Fine Arts in New York, New York, and the Royal Academy of Fine Arts in Munich, Germany, where he was taught by Carl von Marr.
Gustave was known for his vibrant, colorful landscapes and often painting at various places in rural Wisconsin.