He landed many of his most famous roles during the early 1970s , such as Major Frank Burns in the blockbuster comedy `` MASH '' ( 1970 ) and the lead role in `` THX 1138 '' ( 1971 ) , as well as Horton Foote 's adaptation of William Faulkner 's `` Tomorrow '' ( 1972 ) , which was developed at The Actors Studio and is Duvall 's personal favorite .
He landed many of his most famous roles during the early 1970s , such as Major Frank Burns in the blockbuster comedy `` MASH '' ( 1970 ) and the lead role in `` THX 1138 '' ( 1971 ) , as well as Horton Foote 's adaptation of William Faulkner 's `` Tomorrow '' ( 1972 ) .