Price, one of Europe's victorious 2002 Ryder Cup side, started the day three strokes behind American Clark Dennis.
But the 50-year-old made five birdies over the first six holes and finished on 14-under-par, one shot ahead of Thailand's Thaworn Wiritchant.
"I'm a little light on Senior titles, so it's nice to get one," Price said.
"I played nice early on and managed to hang on at the end."
After the test offered by the course at Vorbeck in Germany, Price's next appearance will be home on Welsh soil at another links course - the Senior Open Championship at Royal Porthcawl Golf Club from 27-30 July.
"This course is ideal preparation," he added. "My game is in good order, we're playing at a local course, I'll be staying at home and there will be home support.
"I can really take some confidence into that week."
Welshman Phillip Price overturned a three-shot deficit on the final day to win his first European Senior Tour title, the WINSTONgolf Senior Open.