|Hometown:||Jundiai, Sao Paulo|
|Previous School:||Colegio Metropolitano|
2014-15: Marrafao registered yet another stellar season for the Navy and Yellow. He went 10-8 overalll, with a 7-4 SAC record in singles. The impressive conference mark earned him his third straight all-conference nod, as he was named a second team All-SAC selection. William went 7-11 in doubles play.
2013-14: Marrafao had an outstanding sophomore campaign for the Navy and Yellow going 13-5 at No. 3 singles and 10-9 in doubles. His play earned him an All-SAC honorable mention singles selection.
2012-13: Marrafao had an excellent year for the Cobras after finishing with a singles record of 15-5 and a doubles record of 15-8. His performance landed him a spot on the All-Conference second team. Marrafao was also named conference player of the week on March 12.
High School: Marrafao played tennis and soccer at Colegio Metropolitano.
Personal: Son of Marlene and Claudinei Marrafao.