Rietrik was born to Fredrik Polénin and Severina Blidberg in 1823, graduated high school in 1845, then studied Ancient Languages, History, and Geography at the University of Helsinki where he earned a bachelor's and master's degree in 1850.

He was an active participant in the Finnish Literature Society, and did fieldwork in Eastern Finland gathering folktales and songs.

[1] He earned his PhD in 1858 with his dissertation, Johdanto Suomen kirjallisuushistoriaan (Introduction to the History of Finnish Literature).

)[3][4] Polén spent the rest of his life teaching Finnish literature and publishing Finnish language newspapers, including the financially unsuccessful Suomen Lehteä (Finland Magazine), Mehiläinen (The Honeybee), and Pellervo; he frequently contributed polemical articles to other newspapers as well.

He also wrote a series of patriotic poems and essays, which were collected and published in Kirjallinen aarreaitta (The Treasure Trove).