In 1990, Shandon enlisted in the Armywhere among other awards; she earned an Army Achievement medal. During this time, she also attended college at night and graduated from her undergraduate studies Magna cum Laude. After receiving an Honorable Discharge from the military, she worked with the Department of Social Services in San Bernardino, California where she studied to take the Law School Admittance Test. Based on her entrance exam scores, Shandon received a scholarship to Thomas Jefferson School of Law. Along with the required courses, she focused on classes which would prepare her to be a trial attorney. Shandon was a part of the Mock Trial team at Thomas Jefferson School of Law and won the intra-school mock trial competition.

Upon graduating law school in 1998, Shandon traveled to Houston Texas where she studied for and passed the Texas bar exam. While awaiting her bar results, Ms. Tonry taught paralegal and other business courses at Kelsey Jenney College in San Diego.

After learning she had passed the bar, Shandon traveled back to Houston where she interviewed for and was offered a position at the Harris County District Attorney's office. In her three + years at the District Attorney's office, Shandon served as a prosecutor in the Justice Courts, County Courts at Law, and District Courts. Her various assignments included Domestic Violence prosecutor, Juvenile prosecutor, Misdemeanor prosecutor, Felony prosecutor, and Chief prosecutor of County Courts 13 and 5. During her stay at the District Attorney's office, Shandon enjoyed a stellar trial record taking over 50 cases to Jury trial during her three years.

In 2002 Shandon left the office to pursue a career in private practice. She focuses her attention solely on those cases arising out of the Criminal or Juvenile courts.