The German started Sunday one shot off the lead but found himself three in front after 10 holes thanks to a birdie-eagle-birdie run from the eighth.
He had to overcome some hurdles on the back nine but managed to par his way home to finish the tournament on 19 under par, two clear of long-time leader Marcel Schneider and last week's winner Kristoffer Reitan, who fired a bogey-free 60 to set a testing clubhouse target.
Australia's Daniel Gale, who carded impressive opening rounds of a 68 and 66 to occupy joint sixth place on Saturday morning, ended the tournament tied at 17th, following back-to-back rounds of 69 to finish on eight under for the tournament.
Fellow Australian Danny List ended on six under to share 27th place with six other players.
HotelPlanner Tour graduate Von Dellingshausen said: "I'm trying really hard not to cry. It's been such a tough journey the last two-and-a-half years with losing the card.
"It's all got me to this stage right here and now I'm here!
"I love playing in Austria. I always play well when I play here for some reason - must be the food!
"It was just amazing to have so many people coming out here cheering for us."
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