Over the next 20 years, he and the Lancaster High School, which included a girls' department, held two Arbor Days annually, complete with afternoon programs lasting sometimes 2-2+1⁄2 hours.

McCaskey considered his work as editor of the Journal his most important contribution, followed by his compilation of many songbooks which were sold throughout the United States.

While he was very well loved and respected by his many students, who called themselves "Jack's boys," he ranked his accomplishments as a teacher and principal below his Journal editorship and songbooks.

In May 1849, McCaskey began boarding with relatives in the city of Lancaster to attend one of the few public high schools opened in the state at that time.

His father (William), mother (Margaret) and his six younger siblings were forced to move from the Leacock Township farm into Lancaster because of financial losses.

He was among the first to publish Christmas carols and songs in his songbooks, and included was "Jolly Old St. Nicholas," the verses of which Lancastrians incorrectly believed he had written.

(Emily Huntington Miller wrote the text as a poem, "Lilly's Secret", which appeared in December 1865 in The Little Corporal; it was set to music most likely by James Ramsey Murray.)