Green’s Dictionary of Slang

(Aus.) a surprising or notable person; an exceptional or unexpected piece of good luck or pleasant event.

1881		S. Aus. Register (Adelaide) 21 Nov. 1/7: [N]one of the various bowlers [...] appeared able to get one ‘out of the bag’.
1892		Goulburn Eve. Penny Post (NSW) 2 Aug. 2/5: Noonan, if he would kick more, would be ‘one out of the bag.’ He has plenty of speed and strength.
1894		Maitland Dly Mercury (NSW) 2 Nov. 3/1: He also bowled Bergin with one out of the bag.
1903		Sydney Sportsman (Surry Hills, NSW) 7 Jan. 2/3: It is a prize packet performance. One out of the bag.
1911		Sydney Morn. Herald 5 Dec. 5/5: In Cotter’s second over he let one out of the bag which smashed Gehrs’s wicket.
1911		Truth (Brisbane) 31 Dec. 6/2: Wilkie has the reputation of being one out of the bag as far as a pleasant chap is concerned.
1920		St George Call (Kogarah, NSW) 15 May 5: [advert] ‘Durand of the Bad Lands’ 5 Reels of excitement, thrills and laughter from start to finish. If you never see another Western Picture, don’t miss this. One out of the bag.
1925		Observer (Adelaide) 23 May 26/5: Coursing [...] The brindle dog is one of out the bag.
1931		Smith’s Wkly (Sydney) 31 Oct. 1/3: ‘WHEAT shows increase of 5d in 3 weeks.’ One out of the bag!
1935		Blyth Agriculturalist (SA) 22 Nov. 2/2: They had been well served by other presidents, and they now had one ‘out of the bag.’ He was a tower of strength and a good citizen.
1947		D. Davin For the Rest of Our Lives 301: You’ve no idea what a good joker Alister was. He was one out of the box, was Alister.
1954		T.A.G. Hungerford Sowers of Wind 44: The only difference is, it was all done with one bloody bomb—that’s what makes it one out of the bag. One place that’s been skittled is like any other, otherwise.
1959		G. Slatter Gun in My Hand 60: Not a bad day, eh? One outta the box.
1972		G.W. Turner Eng. Lang. in Aus. and N.Z. 107: The list of items valid in both countries [...] would include one out of the box ‘an excellent one’.
2003		McGill Reed Dict. of N.Z. Sl. 148: one out of the box An outstanding object or achievement, such as a spectacularly fine day. Contraction of American out of the band box, a new item. ANZ 1920s.