The move comes as Burton's, the UK's second-biggest biscuit manufacturer, announced a "new era" of investment.
Newiss is expected to help Burton's grow its portfolio and expand into new markets. He will be responsible for commercial sales activities including customer management, retailer brand, international, category management and sales and operations planning.
His appointment follows a restructure at Burton's last year that resulted in a £331.9m buyout by the company's lenders CIBC and Apollo Global Management.
"Steve will be invaluable in unlocking the potential of our business afforded by the significantly up-weighted investment following the successful completion of our corporate re-financing last year," said Burton's CEO Ben Clarke. The experience Newiss had in the UK and internationally made him "arguably the top sales operator in Europe", he added.
"We wanted to bring in someone very seasoned to drive our commercial agenda forward further and faster," Clarke said. "This is the start of a new era for Burton's Foods. We're pretty bullish about the future and, following the re-structure, we've got the wherewithal to attract top talent to help us accelerate our development."
Newiss was formerly sales director of Terry's Suchard at Kraft before rising up the ranks to become vice president of European sales in 2001 and then vice president of international development in 2003.
"There are significant growth opportunities for the business," Newiss said. "My focus will be developing a best-in-class and efficient integrated commercial proposition that has our customers at heart."
According to Clarke, last year's re-financing had allowed Burton's to increase investment in three key areas brands and own-label in the UK; its export business; and upping capital investment.