Byron James (Marlon Archey), and Merilee Gunderson (Whitney Kershaw), as well as his home life, as he learns to live with Polly's three daughters, Elizabeth, Robin, and Casey.

At the beginning of the second season, the MacGillis family moves to Camp Hollister (based on Marine Corps Base Quantico), where Mac must adapt to the role of staff secretary (or "staff weenie") and the crazy antics of Commanding (Brigadier) General Marcus C. Craig, Aide-de-Camp 1st Lt. Eugene Holowachuk (who transferred with Major MacGillis from Camp Singleton), and Gunnery Sgt.

Alva "Gunny" Bricker, the General's secretary, a no-nonsense Marine, who despite her brusque nature and unprepossessing physical appearance, is the target of many enthusiastic (and unseen) suitors.

Character development increased during the second season, such as the revelation that MacGillis is a former member of the United States Marine Corps Silent Drill Platoon.

Major Dad incorporated the 1991 Persian Gulf War into storylines, depicting Mac staying stateside instead of going to Saudi Arabia as he wanted.