In 1876, Trier began publishing a series of biographies and character studies of various authors called Kultur-Historiske Personligheder.
In 1879, he began publishing Vor Ungdom, a pedagogic periodical, with School-Inspector P. Voss of Christiania.
He also published Pædagogiske Tids- og Stridsspörgsmaal from 1892 to 1893, and in 1901 he wrote on the medieval history of Copenhagen in a text called Gaarden No.
He was first elected a member of the Danish Chamber of Deputies in 1884, and he held his seat with interruptions until 1909.
[3] He was originally a member of the Liberal Party, although he had an independent position and later joined the Radical Left.
His only son was author Sigurd Trier, whose death in 1920 negatively impacted his health.