In 2009 he was ranked his high of # 227 in singles, and in 2012 he was ranked his high of # 82 in doubles. In Davis Cup play, through September 2013 he is 21–14 in singles, and 12–10 in doubles. As of September 2013, he held the Uruguay record for most Davis Cup wins in doubles.
His father is Geraldo, and his mother is Judith. He has a brother named Andres, and a sister, Celine. Felder began playing tennis at four years of age.
As a junior, his career-high rankings were # 4 in singles, and # 5 in doubles, both in 2002.
In February 2007 he played for the Uruguay Davis Cup team against Jamaica.