On the final matchday of the season, Guly scored the opening goal in a 2–1 away win against Perugia that won Milan the 1998–99 Scudetto.
He was a remember of Argentina's 1999 Copa América squad that reached the quarter-finals of the tournament, losing out to eventual champions and South-American rivals Brazil.
[4] Diego Simeone left Estudiantes in December 2007, claiming a supposed lack of the club's commitment to sign appropriate reinforcements for the 2008 Clausura and Copa Libertadores.
Guly also took up the same position with the same coaching staff at River Plate in 2008 and San Lorenzo in April 2009, where he also was the manager of the club's reserve team.
In June 2013, he was the assistant manager of Nelson Vivas, who Guly formerly had worked together with in the coaching staff of Diego Simeone.