Swindon secured automatic promotion to League One with a draw that was also enough to hand the title to Walsall.
Jerel Ifil's first league goal of his career - a near-post diving header - put Swindon in front.
Walsall manager Richard Money was sent-off for over-protesting the award of a Swindon throw-in.
But Dean Keates scored a dramatic equaliser from 20 yards with virtually the last kick of the match to earn Walsall's first title since 1960.
With Hartlepool going down to a late defeat it meant Walsall will go up as champions.
Swindon were also celebrating at the end with manager Paul Sturrock earning the fourth promotion of his managerial career.
Swindon: Phil Smith, Jack Smith (Westwood 19), Nicholas, Ifil, Vincent, Roberts, Peacock, Pook, Zaaboub, Corr (Jutkiewicz 89), Sturrock.
Subs Not Used: Brown, Timlin, James.
Booked: Roberts, Pook, Corr.
Goals: Ifil 52.
Walsall: Ince, Pead, Fox, Gerrard, Westwood, Harper, Dobson, Keates, Demontagnac (Sam 63), Butler, Benjamin (Wrack 78).
Subs Not Used: Bossu, Wright, Smith.
Booked: Keates, Gerrard.
Goals: Keates 90.
Ref: M Jones (Cheshire).