Born into a musical family in Mococa, São Paulo, Brazil, Sérgio Assad began creating music for the guitar not long after he began playing the instrument. He learned Brazilian folk melodies from his father and by age 14, he was arranging and writing original compositions for the guitar duo he had formed with his brother, Odair. At the age of 16, he and Odair began their studies under the best-known classical guitar teacher in Brazil at the time, Monina Távora, a former disciple of Andrés Segovia. Sergio later went on to study conducting at the Escola Nacional de Música in Rio de Janeiro, and worked privately with Brazilian composition teacher, Esther Scliar.  

Over the last thirty years Assad has concentrated most of his efforts on building a repertoire for the guitar duo. He has extended the possibilities of the two-guitar combination through his arrangements of Latin American music by composers such as Piazzolla, Villa Lobos, Ginastera and Gismonti as well as Baroque and Modern music by Scarlatti, Rameau, Soler, Bach, Mompou, Ravel, Debussy and Gershwin among many others. He has completed over 300 arrangements for different chamber music settings. He has been arranger for Gidon Kremer, Dawn Upshaw, YoFYo Ma, Nadja Salerno Sonnenberg, Paquito D'Rivera, Turtle Island String Quartet, and LA Quartet among others.  

As a composer Assad has completed over a hundred works for guitar, many of which have become standards in the classical guitar repertoire. Pieces like Aquarelle, Fantasia Carioca, Farewell, Sonata 1, and Eli’s Portrait are part of the repertoire of many well-established guitarists today. In 2008 Sergio Assad was awarded the first prize in the Latin Grammy for his original composition Tahhyya Li Ossoulina.  

Assad’s orchestral compositions include the ballet "Scarecrow", the concerto "Mikis" for guitar and strings, "Fantasia Carioca" for two guitars and chamber orchestra, "Interchange", a concerto for guitar quartet and orchestra premiered by the Los Angeles Guitar Quartet with the San Antonio Symphony in 2009, the concerto "Originis" for violin, guitar duo, and orchestra recorded live with the Orquestra Sinfonica do Estado de Sao Paulo featuring the Assads and Nadja Sonnemberg as soloists, the concerto "Phases" for guitar duo and orchestra premiered in 2011 by the Seattle Symphony Orchestra with the Assad Brothers as soloists and the Concerto Popular do Rio commissioned by the GFA and the Cordoba Guitar Festival premiered in June 2015 with Pablo Villegas as soloist.