The Owls have now paid out £125,000 to sign the Scot, beating off competition from three other clubs including Hull City. He will join Lee Peacock who also recently moved to Hillsborough despite interest from City.
Wednesday boss Chris Turner described MacLean as "one of the hottest prospects to come out of Scotland" after signing him on a three-year deal.
Peter Taylor's quest to buy a replacement for Ben Burgess continues. An announcement is expected to be made this week as to who the last of City's summer signings will be, with Swindon's Sam Parkin and Oldham's Scott Vernon being two names speculated about.