Gabriel Valdez is a native San Antonian who has been teaching band since 2011. He currently serves as the Director of Bands at O’Connor High School. Prior to his current appointment, he served as Associate Director of Bands at O’Connor High School from 2018–2025. Before joining O’Connor, he was the Associate Director of Bands at Brackenridge High School from 2013–2018 and Band Director at Poe Middle School from 2011–2013.

As Director of Bands at O’Connor High School, Mr. Valdez oversees all aspects of the band program. Throughout his tenure at O’Connor, he has conducted the Wind Ensemble, co-directed the Full Orchestra, co-taught the Symphonic Winds and Concert Band ensembles, and co-directed the Panther Marching Band. While at Brackenridge High School, he directed the second band, served as orchestra director, and co-directed the color guard program. During his tenure at Brackenridge, Mr. Valdez’s band was one of the few San Antonio ISD non-varsity bands to consistently earn Superior ratings at UIL Concert and Sight-Reading Evaluation. He also led the school’s first full orchestra to UIL competition, where the ensemble received Excellent ratings. During his time co-teaching color guard, the program experienced significant enrollment growth and earned its first medals at the Texas Educational Colorguard Association (TECA) Championships.

Mr. Valdez is a graduate of the University of Houston, where he was a member of the Spirit of Houston Marching Band, Concert Band, and Symphonic Band. While at the university, he had the privilege of studying under David Bertman, Tom Bennett, and Marion West. He was also mentored by renowned Texas band educator Eddie Green and studied trumpet with George Chase. Mr. Valdez earned a Master of Education in Educational Leadership from Trinity University in 2025.

Mr. Valdez is married to his wife, Crystal, and together they have two children and a dog named Rio. He is a member of Phi Mu Alpha Sinfonia and the Texas Music Educators Association.

Mr. Cuellar begins his 27th year in music education and his first year as an Associate Director of Bands at Sandra Day O’Connor High School. Prior to joining the O’Connor Band staff, he spent three years at Thomas Jefferson High School in San Antonio ISD and 23 years in Northside ISD, serving at John Jay High School (2001–2005), Earl Warren High School (2005–2008), and Louis D. Brandeis High School (2008–2023).

During his time at John Jay and Warren, Mr. Cuellar assisted with the Varsity Marching Band and Symphonic Band while also teaching Music Theory I. His responsibilities included directing the Concert Band, Jazz Ensemble, Jazz Combo, and Mariachi Ensemble.

In 2008, Mr. Cuellar became one of the original staff members at Louis D. Brandeis High School. While at Brandeis, he assisted with the Varsity Marching Band, Symphonic Band, and Freshman Band, conducted the Non-Varsity Band, and was responsible for developing the school’s Jazz Studies program. Under his leadership, the program grew into one of the most competitive and recognized high school jazz programs in South Texas.

Mr. Cuellar also founded the South Texas Jazz Festival, creating an opportunity for middle and high school musicians to perform, learn from leading professionals, and experience world-class jazz performances within their community. Throughout his career, his jazz ensembles have hosted and shared the stage with renowned musicians and ensembles including Arturo Sandoval, Tamir Hendelman, Curtis Calderon, The Wasabi Big Band, Dr. Adrian Ruiz, Henry Brun, Kirk Covington, Ron Wilkins, the world-famous Glenn Miller Orchestra, Los Angeles studio trumpet legend Rick Baptist, and Los Angeles studio drummer and percussionist Bernie Dresel.

From 2018 through 2023, Mr. Cuellar also served as the TMEA Region 29 Jazz Coordinator in San Antonio.

A native Texan, Mr. Cuellar grew up in the San Antonio area and attended Central Catholic High School before continuing his education at St. Mary’s University. He earned both a Bachelor of Arts in Music Education and a Bachelor of Business Administration in Human Resources. While at St. Mary’s, he was actively involved in the Jazz Orchestra, Concert Band, Rattler Pep Band, and vocal ensembles. In 2024, Mr. Cuellar earned his Master of Music Education from Lamar University.

Mr. Cuellar’s connection to O’Connor dates back to the beginning of his career. In the fall of 2000, he completed his student teaching at Sandra Day O’Connor High School under Mr. Wallace Dierolf, Mr. Roland Sandoval, and Mr. George Garza. He is excited to return to O’Connor and contribute to the continued success and tradition of the Panther Band program.

Outside of music education, Mr. Cuellar enjoys spending time with his wife, Natalie, and their three children.

Mr. Marin is an Associate Director of Bands at Sandra Day O’Connor High School, where he serves as the Director of Percussion and Jazz. Entering his ninth year at O’Connor, he oversees all aspects of the percussion program, including the marching percussion section, front ensemble, percussion ensembles, concert percussion, and percussion instruction throughout the band program. He also directs the O’Connor Jazz Bands and assists with the school’s concert ensembles.

Prior to joining the O’Connor Band staff, Mr. Marin taught at North Shore Senior High School, Pearland High School, and James Bowie High School in Arlington. Throughout his teaching career, his percussion ensembles and sections have earned numerous awards and recognitions in marching, indoor, concert, and solo and ensemble settings. At O’Connor, the percussion program has earned multiple Best Percussion awards, while the indoor percussion program has achieved notable success, including a third-place finish at the TCGC State Championships in Open Class and a first-place finish in A Class. 

Outside of his work at O’Connor, Mr. Marin has remained active in the marching arts. He  was involved with Violet Crown Independent from 2017 to 2020, beginning as a quad technician before later serving on the admin team. He has also served as an audio tech with the Spirit of Atlanta Drum and Bugle Corps and judges indoor percussion/winds with the Texas Educational Colorguard Association (TECA). 

Mr. Marin earned his Bachelor of Music in Music Education from the University of North Texas and later returned to UNT to earn a Master of Education in Educational Leadership. He is passionate about helping students grow not only as musicians, but also as disciplined, resilient, and confident young adults. In his spare time, Mr. Marin loves to travel, spend time with his daughter and listening to live music. 

Ms. King is the Colorguard Director at Sandra Day O’Connor High School, where she is currently entering her fifth year with the O’Connor Band program. She oversees all aspects of the colorguard program, working with students throughout the marching band and winterguard seasons. She is passionate about creating an environment where students can grow as performers while developing confidence, discipline, teamwork, and a lifelong love for the performing arts.

Prior to joining the O’Connor staff, Ms. King served as the Colorguard Director at Brandeis High School for five years and as the Colorguard Director at Fossil Ridge High School in Keller, Texas, for two years. Throughout her career, she has enjoyed helping students develop their skills in dance, movement, and equipment while creating memorable and meaningful performance experiences.

In addition to her work at O’Connor, Ms. King is currently on staff with Industry Independent A Winterguard. She enjoys remaining active in the winterguard community and continuing to grow as an educator and designer within the marching arts.

Above all, Ms. King believes that colorguard is about much more than what happens on the performance floor or football field. She strives to help her students become confident performers, supportive teammates, and strong young adults while creating a program where students feel challenged, valued, and proud of what they accomplish together.

Outside of colorguard, Ms. King loves traveling and all things Disney. Her favorite role, however, is being a mom to her two daughters. She loves spending time with them, traveling together, laughing, and being as silly as possible whenever she gets the chance.