Son of The­o­dor Flied­ner, found­er of the Kai­ser­swerth Dea­con­ess In­sti­tute, Fe­der­i­co was ed­u­cat­ed at the Gym­na­si­um in Güt­ers­loh, stu­died the­ol­o­gy at Halle (1864-6) and earned his PhD at Tü­bing­en (1867). He served as a nurse in the Austro-Pruss­ian war of 1866, and taught school for a year in rur­al Hild­en. Af­ter or­din­a­tion in 1870, he left Germany to be a mis­sion­ary to Spain, set­­tling in Ma­­drid and be­com­ing a chap­lain at the Ger­man em­bas­sy. He learned Span­ish, at­tend­ed a Span­ish high school, and stu­died me­di­cine at the Un­i­ver­si­dad Cen­tral.

Flied­ner was in­stru­ment­al in cre­at­ing what is now known as the Igle­sia Evan­gél­i­ca Es­pañ­o­la. In 1873, Flied­­ner found­ed the Li­bre­ría Na­ci­o­nal y Ex­tran­je­ra, an ex­ten­sive col­lect­ion of text books and per­i­od­i­cals. Among these was The Child­ren's Friend, pub­lished from 1874 to 1939.

Flied­ner wrote bi­o­graph­ies of John How­ard, Eliz­a­beth Fry, mis­sion­ary-ex­plor­er Da­vid Liv­ings­tone , Mar­tin Luther (1878), and his own par­ents, The­o­dore Flied­ner of Kai­­ser­s­werth (1883) and Car­o­line Flied­ner of Kai­sers­werth (1883). He al­so wrote an au­to­bi­o­graphy, pub­lished first in Ger­man in two vol­umes (Aus mein­em L­eben, 1901-3), then trans­lat­ed in­to Spanish and pub­lished posthumously in the Christ­ian Mag­a­zine (Nos. 513 to 553). He start­ed a Spanish trans­la­tion of the New Test­a­ment with notes from Frenchman Ed­ouard Faivre.

1. Alma Ben­dice al Señ­or
2. De Bo­ca y Cor­a­zón
3. ¡Oh Ros­tro En­san­gren­ta­do!
4. ¡Oh San­tí­si­mo, Fe­li­císi­mo!
5. Se Oye un Son en Al­ta Es­fe­ra