Sir Dave Lewis will take the helm of the brewing giant on 1 January, after former chief executive Debra Crew stepped down in the summer after two years in the role.
Despite a rise in Guinness sales, the firm has been struggling with weak sales across its entire range, and its shares recently hit a 10-year low.
Following the announcement of Sir Dave's appointment on Monday, Diageo's share price rose by 7% in early trading.
'Drastic Dave'
Diageo owns well-known brands such as Johnnie Walker whisky, Smirnoff vodka and Captain Morgan rum, but it has seen weakness in sales in key markets, particularly the US and China.
Sir Dave was chief executive of Tesco for six years until 2020, and before that spent almost 30 years at consumer goods giant Unilever. He will step down from his current role as chairman of health firm Haleon.
Sir Dave said: "The market is facing some headwinds, but there are also significant opportunities."
"I look forward to working with the team to navigate these challenges and to seize some of the opportunities in a way that creates value for shareholders."
Diageo saw its operating profit fall to £3.2bn in the year to June – down almost 28% compared with the same period last year – and net sales fell by 0.1%.
The company said there was "still much to do" in a challenging year, and cited "pressure on consumers".
Last week, Diageo forecast that net sales growth would be flat or slightly down in the coming year due to a "weak US consumer environment" and lower sales in China. Rising inflation has led people to cut back on spending in recent months, and consumers are reducing their spending on alcohol and eating out.
The firm is also grappling with changing drinking habits among young people, who tend to drink less alcohol than previous generations.
Dan Coatsworth, head of markets at AJ Bell, said: “Dave Lewis will have to get Diageo back on track quickly.”
“His style is to listen carefully to customers and suppliers and find out what went wrong. The focus will be on fixing things, not on long-term growth.” Mr. Coatsworth said the new boss earned the nickname “Drastic Dave” while working at Unilever, “because he had the ability to make big decisions without just tinkering around the edges.”
“At Tesco, he left saying his job of stabilising the business was done, rather than staying to take the business to the next level. One could argue he will take the same approach at Diageo.”
Sir Dave will replace Nic Jhangiani – who is Diageo’s chief financial officer and has been acting as interim chief executive since Ms. Crew’s resignation in July.