Hermann Albert Kobold was born in Hanover, Germany third of five children of the carpenter August Kobold and his wife Dorothea Kobold (née Brandt). From 1877 to 1880, he studied mathematics and natural sciences at the University of Göttingen and attained a doctorate in astronomy in July 1880 with Wilhelm Klinkerfues as his adviser.
Subsequently, he was an assistant at the private observatory of Miklos von Konkoly-Thege in O'Gyula, Hungary (now Hurbanovo, Slovakia). After the participation in an expedition to observe the 1882 transit of Venus in Aiken, South Carolina he worked some years on its data analysis in Berlin.
In 1887, Kobold was appointed to the observatory in Strasbourg, France (German Empire at the time). That same year, he married Dorothea Brandt, with whom he had five children. In 1888, he became private lecturer and in 1900 extraordinary professor at the University of Strasbourg; two years later he went to the University of Kiel as an observator and extraordinary professor.
By intensive observations he discovered 22 previously unknown, smaller galaxies of the Coma galaxy cluster.
From 1908 to 1938 he was the publisher of the astronomy journal Astronomische Nachrichten. An asteroid discovered by Karl William Reinmuth received the name 1164 Kobolda in Kobold's honor in the 1930s.
On 11 June 1942, Kobold died in Kiel, Germany.