He studied in the Jyväskylä Teacher Seminary and graduated in 1901.
He was granted with the title of Professor in October 1943. After graduation he first worked in Uusikirkko but in 1904 he moved to Oulu to work as a crafts and arts teacher in a school for deaf-mute children. He wrote 21 books, hundreds of journal articles, took over eight thousand photographs and made thousands of drawings on his trips.
Since 1908 Paulaharju also worked as a curator for the Northern Ostrobothnia museum in Oulu.
Nowadays Paulaharju"s study and library can be found in the museum. Samuli Paulaharju is buried in the Oulu Cemetery.