The defending champions needed less than three hours to dismiss out their visitors for 96, and then moved into a lead of 113 as Knight and Dominic Ostler (57) helped them to the close at 209 for 4.
Knight's highest first-class score since leaving Essex in the winter included 12 fours from 191 balls, and his third-wicket partnership with Ostler was worth 147 in 46 overs.
Yorkshire's collapse was instigated by Allan Donald (5 for 21) and Scottish seamer Dougie Brown, who claimed 4 for 35. The in-form Martyn Moxon and David Byas quickly fell to Donald, and the South African polished off the tail with 3 for 9. This completed his fourth five-wicket return against Yorkshire in five meetings since 1991.
Brown dismissed the Australian Michael Bevan with his second delivery and his haul of four middle-order victims also included Richard Blakey, lbw for a top score of 18.
Yorkshire's total was their lowest at Edgbaston for 31 years, but their bowlers were unable to achieve similar success on a grassy pitch. Peter Hartley bowled Andy Moles for 22, then in the 63rd over he dislodged Knight with a slip catch by Byas. Three balls later Ostler was bowled as he backed away to cut Michael Vaughan.Reuse content