If you pass Tommy Emmanuel walking down the street, you might not give him a second glance. You might think he’s just another average middle-aged guy dressed like one of those vanilla L.L. Bean catalogue models.

That average-guy look is deceiving; put a guitar in Emmanuel’s hands and amazing things happen, things that shouldn’t happen with only a guitar and a couple of hands. It’s jaw-dropping stuff.

Many is the singer/songwriter who picks up a guitar, strums a few milquetoast chords and warbles with harmonious emotion. Emmanuel’s relationship to them is rather like that of Jimi Hendrix to that guy in the Kingsmen who flailed away at the three chords of “Louie, Louie” (not that there’s anything wrong with a well-delivered flail, of course).

When he plays, Emmanuel usually bears a persistent smile. No overly serious funk face or cool-guy posturing is in evidence. He’s in command of his instrument, no matter how complex or quick the notes become (they get blistering), and he seems to be enjoying himself with abandon.

In addition to all the fretboard fireworks, Emmanuel is a wildly inventive entertainer. He punctuates his guitar pieces, most but not all instrumentals, with humorously timed string hits and bent notes, and he all but dances while he does it. Few entertainers seem to be quite so at home on stage.

One key to Emmanuel’s inventive six-string heritage is the strange group of letters that follows his name on his website, “CGP.” That stands for “Certified Guitar Player,” a degree all the rarer for only ever being bestowed by one man: the late Chet Atkins. It was that giant of guitar playing who inspired Emmanuel early on in his rural Australian childhood, and later Atkins became a mentor to Emmanuel, eventually offering him the use of those three letters.

It’s a testament to Atkins’ tremendous influence on Emmanuel’s complex finger-picking style that the Country Music Association gave him a Global Country Artist of the Year Award, but to think of him as merely a country player is hardly accurate. His methods range from finger-picking straight out of Atkins’ repertoire to regular picking to using his acoustic guitar as a percussive instrument, knocking and slapping its body and even using a drum brush. His repertoire of originals and covers borrows from jazz, rock, country and folk, and often departs for all sorts of unexpected musical destinations within the space of a few minutes. He brings to those disparate styles an uncanny ability to drive (apparently any) song with just one guitar.

The renowned Australian showman brings his six-string madness to Northampton this week.

Tommy Emmanuel: Sept. 12, 8 p.m., Calvin Theater, 19 King St., Northampton, (413) 586-8686, www.iheg.com.