He was notable for his World War II service in the China Burma India Theater and his command of the Sixth United States Army.

[8] In World War II Cannon served in the China-Burma-India Theater, advancing to brigadier general and chief of staff for the Northern Combat Area Command.

[9][10][11][12][13][14][15][16] After World War II Cannon served as chairman of an Army board which interviewed and made recommendations on applicants for commissions as officers.

[24][25][26][27][28][29] Following his Philippines assignment, Cannon was appointed Service Special Assistant to the Joint Chiefs of Staff for Mutual Defense Advisory Pact Affairs.

[30] Cannon served as deputy commander and chief of staff for United States Army Pacific, receiving promotion to lieutenant general.