He started his career in Nacional, where he played from 1994 to 2000, winning the Uruguayan league titles of 1998 and 2000. He left Nacional to join Serie A club AS Roma in 2000 for USD 5.8M, where he won the 2000/2001 Scudetto. Guigou left for Siena on loan in summer 2003 and sold to Fiorentina in July 2004 for a nominal fee of €516. In June 2006 he left for newly relegated Serie B side Treviso as part of Massimo Gobbi and Reginaldo's deal.
After the club was excluded from professional football in 2009, he was released for free by the federation and later joined Nacional, back in Uruguay. He played for Uruguay in the 2002 FIFA World Cup.
^"Acquisiti Gobbi e Reginaldo, ceduto Guigou". ACF Fiorentina (in Italian). 24 June 2006. Retrieved 30 June 2006. La Fiorentina comunica di aver acquisito a titolo definitivo le prestazioni sportive del centrocampista Massimo Gobbi......e nell’ambito della stessa operazione di aver acquisito a titolo di compartecipazione le prestazioni sportive dell’ ...Reginaldo......e inoltre di aver ceduto a titolo definitivo le prestazioni sportive del...Guigou......[dead link]