Composer. He studied organ with Louis Homilius and graduated from St Petersburg Conservatory with silver medal in 1908. His teachers in composition there were Nikolai Rimski-Korsakov and Aleksandr Ljadov. After the completion of studies Saar worked in Tartu as music teacher. In 1921 he moved to Tallinn being free-lance composer for the most part. He often performed as organist. From 1928 to 1929 Saar worked as an editor in Muusikaleht [Musical Magazine].

During the years 1932–1943 Saar lived in his paternal home in Hüpassaare where he later spent all his summers. In 1972 there was opened his museum. From 1943 to 1956 Saar was a professor of composition at the Tallinn Conservatory. Among his students there were Ester Mägi and Harri Otsa.

Saar was one of the founders of Estonian national professional music, especially in the field of choral music. At the beginning of his career Saar was influenced by modern movements in European music of that time – the expressionism (in Must lind [Black Bird], a solo song) and the impressionism (the preludes for piano). In his piano piece Skizze there can be found even atonal language.

Since the 1920’s his music does more and more express distinctive national character. First of all it was a direct influence of the Estonian archaic folk song which arose increasing interest among Estonian intelligence at that time. Saar was one of those who systematically collected folk songs (expeditions in 1907 and in 1910) and analyzed them closely.

Some of Saar’s songs have very simple texture and have often been performed on song festivals. On the other hand there is a lot of songs by Saar quite difficult even for professional interpreters.

Saar revealed the new approach to harmony and texture of choral song as well as to the relation between the verbal text and music. Former composers have treated the Estonian folk song as only melodic material and harmonized and rhythmized it in the spirit of German Late Romanticism. Saar saw folk song as a whole where the word, melody and style of performance are inseparably connected. He apprehended the richness and possibilities of phonetics, assonance and alliteration of Estonian dialects and treated therefore the verbal text as musical component in his songs. The distinctive harmony of Saar’s music is a synthesis of classical (romantic) sequences and combinations influenced by modal musical thinking.

Songs for mixed choir:
* Põhjavaim [Northern Spirit]
* Seitse sammeldunud sängi [Seven Mossy Beds]
* Muru kasvab mulla pääle [The Grass Is Growing On The Earth]
* Luule, see ei tule tuulest [Rhymes Do Not Come With Wind]
* Oh kodumaa [Oh My Homeland]
* Allik [Wellspring]
* Mälestus [A Memory]
* Meie Leenikene tantsib [Our Little Leeni Is Dancing]
* Jaan läheb jaanitulele [John Is Going On St. John’s Fire]
* Mis sa nutad, tammekene [Why Are You Weeping Oak Tree]
* Kõver kuuseke [Crooked Fir]

For male choir:
* Küll ma laulaks [I Would Sing]

For female choir:
* Päikesele [To the Sun]

Solo songs:
* Must lind [Black Bird]
* Lauliku talveüksindus [Singer’s Winter Loneliness]

Piano music:
* 20 rahvaviisi [20 Folk Songs] (1910–1913)
* Eesti süidid [Estonian Suites] (1939, 1941, 1948)
* Prelüüd ja fuuga G-duur [Prelude and Fugue in G]
* Humoresk [Humoresque]
* Skizze, preludes (1905–1940)

Records:
* Eesti Rahvusmeeskoor [Estonian National Male Choir], Küll ma laulaks [I Would Sing]. Conductor Ants Soots. Mart Saar Küll ma laulaks [I Would Sing], Hällilaul [Lullaby] 1997, ERCD 024