<P> The series follows a family of six , and later seven , and stars Frankie Muniz in the lead role of Malcolm , a somewhat normal boy who tests at genius level . While he enjoys his intelligence , he despises having to take classes for gifted children , who are mocked by the other students who call them `` Krelboynes '' . Jane Kaczmarek is Malcolm 's overbearing , authoritarian mother , Lois , and Bryan Cranston plays his immature but loving father , Hal . Christopher Kennedy Masterson plays eldest brother Francis , a former rebel who , in earlier episodes , was in military school , but eventually marries and settles into a steady job . Justin Berfield is Malcolm 's dimwitted older brother Reese , a cruel bully who tortures Malcolm at home , even while he defends him at school . Younger brother Dewey , bitter about his ruined childhood , smart , and musically talented , is portrayed by Erik Per Sullivan . At first , the show 's focus was on Malcolm , but as the series progressed , it began to explore all six members of the family . A fifth son , Jamie , was introduced as a baby at the end of Season 4 . </P>
who plays the dad in malcom in the middle
Bryan Cranston