Pietro learned the oeuvre alongside his younger brother Bartolomeo at his father's workbench. As Giuseppe's firstborn, he rightfully pretended to inherit the Cremonese workshop. Instead, Pietro left their hometown as soon as he turned 20y.o., still unmarried (quarrelsome, no doubt, by XVII-century social conventions). Knowingly or coincidentally, Pietro II followed his namesake uncle's sake—seventeen years ago, [url=https://discogs.com/artist/7238307]Pietro di Mantova[/url] (1655—1720), their father's elder brother, also quit Casa Guarneri and gave up on the family inheritance to establish his business in Mantua.

House of Guarneri, despite at least two decades of "heads-up" against Antonio Stradivari, struggled tremendously ever since the aspiring luthier opened his workshop nearby. Most experts agree that Casa Guarneri's patriarch, their grandfather, even though one of Nicolo Amati's closest apprentices, was too conservative and lacked personal creativity in his builds while rejecting any change and "frivolous" experiments—as evident in Pietro di Mantova's story. Whereas other Casa Amati alumni (both immediate and "in spirit") proliferated in advancing, improving, and building upon "grand Amati" models, House of Guarneri stagnated and kept falling behind on the competitive Cremonese market.

Thus, young Pietro was escaping the sinking ship, in a sense, rather than walking away from the desirable inheritance. He moved to Venice in 1717, the same year that Carlo Tononi arrived from Bologna, and two young luthiers soon began working for Matteo Sellas at his prosperous Venetian shop. Curiously, Pietro kept signing his builds as 'Petrus Guarnerius, Filius Joseph; Fecit Cremone' until at least 1721. He only embraced the new 'Cremonenſis Fecit Venetis' label after 1725. Pietro married Angiola Marie Ferrari in Apr 1728, and they had ten children together, eventually. (None of whom continued Pietro's lineage). Unlike Pietro di Mantova, he didn't "burn the bridges" as dramatically and kept his father's name as part of his luthier's label for his entire life. In 1740, following their father's death, Pietro traveled back to Cremona to sell the rest of Casa Guarneri with Del Gesu, apparently in a friendly and amicable manner.

In his instruments, Pietro Guarneri masterfully intertwined Cremonese background with "Venetian school," inspired by Giovanni Tononi, Matteo Goffriller (especially in cellos), and, perhaps, Domenico Montagnana's work.

Notable 'P.Guarnerius fecit Venetis' players
𝄞 Carl Flesch performed on the 1757 violin (purchased to replace his iconic 1725 "Brancaccio" Stradivari)
𝄞 Wanda Wilkomirska played 1734 'P. Guarneri'
𝄞 Jovan Kolundžija, Serbian violinist, 1754 violin
𝄞 Beatrice Harrison played one of his cellos