Not only has he been honored as the district's Teacher of the Year, but he was the center of attention on Oct. 13 for a celebration called "Thanks a 1000."
That event drew past and current students, parents, alumni, school board members, and out-of-town friends and family members, who filled the stadium to show their appreciation.
Amador Principal Jim Hansen called Grantham "the embodiment of our community of character," and led students in reciting the creed Grantham teaches to all his students: "We before me, say kind words, do kind things, and take care of those around you."
Speakers projected taped greetings from those who couldn't attend.
The highlight of the day was a visit from Grantham's high school band director, mentor and friend Bob Parker, a name familiar to all of Grantham's students.
Halfway through what was purportedly a recorded speech, the audio system dissolved into static and Parker entered the stadium.
Parker recalled the gangly 16-year-old trombone player as a nitpicker for detail and sensitive to the feelings of others, noting Grantham once corrected him for saying, "Shut up."
"From that day I changed the way I did things," Parker said. "Jon made me a better teacher and a better person."
Grantham has also brought out the best in his students: His four concert ensembles, two jazz bands, winter percussion and winter guard all consistently earn high honors at competitions. Grantham's influence has increased band membership from 140 to 282, the largest in school history and about 12% of the student population.
The love that students have for Grantham was evident in the gifts that were presented to him. A student/pilot gave an aerial photograph of the band, a parent painted an oil portrait, a former drum major, now a sportscaster in Indiana, sent an audio greeting in the form of a sports update, a seamstress gave a teddy bear in a band uniform, and event organizers, Sally Baker and Marilyn Palowitch, presented hundreds of thank you letters bound in purple albums.
"It was a day I will never forget," said Grantham. "It's been a magical decade and I look forward to the next one. It makes me want to work harder, because when you feel someone is behind you it makes you want to exceed expectations."