His innovations in notation of time-values were fundamental to the music of the Italian ars nova, as was his work on defining the modes and refining tuning.
His two major treatises seem to have been written between 1317 and 1319, shortly before Philippe de Vitry produced his Ars nova (c. 1322), which gave its name to the music of the age.
Only three motets have been reliably attributed to Marchetto, one of them due to his name appearing as an acrostic in the text for one of the parts (Ave regina celorum/Mater innocencie).
Marchetto preferred to widen major intervals and narrow minor ones for melodic effect, the opposite of what the later meantone temperament does.
The Lucidarium also included one of the earliest texts addressing the relationship between composer – Marchetto used the word musician, borrowing from Boethius's definition in De institutione musica libri quinque – and performer.
The Rossi Codex, which is the earliest surviving source of secular Italian polyphony and which contains music written between 1325 and 1355, shows obvious influence of Marchetto, especially in its use of his notational improvements.