Professional Trujillo made his professional debut with
UNAM Pumas on October 26, 1996, in a 3–0 win over
Toluca. In the
Verano 2001 he transferred to
Santos Laguna, when Santos won the
Verano 2001 championship. Trujillo went back with
Pumas in the
Invierno 2001, where he would leave until the
2003 Apertura to
Monarcas Morelia. With Morelia he would play until the
2007 Clausura, and would feature in more games than with any other team. In 2007, Trujillo signed a 2-year contract with
Skoda Xanthi of
Greece, but for personal reasons, he left the team. Trujillo played with
Atlante for the
Clausura 2008. He signed for
Chivas USA in March 2009, just before the new season. Trujillo started 18 games and made three substitution appearances for Chivas USA in his first season. He became a regular starter for the team in his second year, and inherited
Jonathan Bornstein's role as captain when Bornstein was not active. Trujillo remained with Chivas USA through the 2011 season. At season's end, the club declined his 2012 contract option and he entered the
2011 MLS Re-Entry Draft. Trujillo was not selected in the draft and became a free agent. Mariano is now a member of Jaguares de Chiapas, Mexican soccer club. No longer an active player, Jose Guadalupe (Jaguares Head Coach) has integrated Mariano to his Coaching Staff upon the 2012 Liga MX season to start July, 20th. Jaguares's coach
Jose Guadalupe Cruz saw him play during a training session with the other players so he convinced Mariano Trujillo to be a team player for the
Copa Mexico where he gave an assist to
Antonio Salazar in a 1–0 win at home against
Necaxa on July 24, 2012.
International Trujillo played two games with the
Mexico national team in 2003, his first against
El Salvador in
Carson, California. He scored his only international goal in a friendly match against
Peru in
East Rutherford, New Jersey. Trujillo was also a member of Mexico's U-20 squad at the 1997 World Youth Championship in Malaysia, alongside former Chivas USA forward Eduardo Lillingston.
International goals ==Honours==