 He was the nephew of Anders Chydenius and the father of Johan Magnus af Tengström, a zoologist, and uncle of Johan Jacob Tengström, a historian and Fredrika Runeberg, a novelist.Tengström wrote the first Finnish-Swedish children's book "Tidsfördrif för mina barn" which was published in 1799 in Turku and later translated into Finnish.He was editor of the Tidningar Utgifne Af et Sällskap i Åbo from 1791 to 1793 and was involved in the founding of the Finnish Bible Society and the Musical Society in Turku .