, ▁many ▁of ▁the ▁show ' s ▁plot ▁lines ▁centered ▁on ▁Jam ie ' s ▁and ▁Grand pa ' s ▁friendship ▁sharing ▁the ▁experiences ▁of ▁growing ▁up ▁and ▁growing ▁old ▁together . ▁ ▁N umer ous ▁scenes ▁in ▁the ▁series ▁take ▁place ▁on ▁A unt ▁Laur ie ' s ▁back ▁por ch , ▁where ▁many ▁of ▁the ▁day ' s ▁problems ▁are ▁discussed ▁and ▁solved . ▁ ▁Cast ▁Br andon ▁de W ilde ▁port rayed ▁Jam ison ▁" J am ie " ▁Francis ▁Mc H um mer , ▁a ▁like able ▁ 7 - year - old ▁or phan ▁who ▁had ▁been ▁sh unted ▁from ▁one ▁un car ing ▁relative ▁to ▁another , ▁until ▁he ▁land ed ▁in ▁A unt ▁Laur ie ' s ▁household . ▁Ernest ▁True x ▁as ▁Grand pa ▁Mc H um mer , ▁a ▁kind red ▁spirit ▁played ▁by ▁the ▁ 6 3 - year - old ▁character ▁actor , ▁who ▁was ▁similarly ▁ignored ▁by ▁his ▁kin . ▁Pol ly ▁Row les ▁as ▁A unt ▁Laur ie , ▁a ▁wid ow ▁and ▁mat ron ▁of ▁the ▁household . ▁There ▁she ▁runs ▁a ▁c ater ing ▁business . ▁Kath le en ▁N olan ▁( as ▁Kath y ▁N olan ) ▁as ▁L iz , ▁Jam ie ' s ▁te en age ▁cousin . ▁Alice ▁Pear ce ▁as ▁An nie , ▁A unt ▁Laur ie ' s ▁helper ▁in ▁the ▁c ater ing ▁business . ▁Pear ce ▁was ▁later ▁best ▁known ▁as ▁the ▁nos y ▁Glad ys ▁K rav itz ▁in