Warne, who has sparked a number of scandals by sending raunchy text messages to women, will be the public face of phone company Messages on Hold.
Callers put on hold will be able to hear a customised message from the cricket superstar.
Warne played a straight bat when asked about the irony of signing with a phone message company, saying the deal had nothing to do with his chequered past.
"If you want to try to tweak it and spin it, you go for it," he told reporters Friday.
Company spokeswoman Emily Northway said her bosses had been chasing Warne for years but insisted the sponsorship agreement was not tongue-in-cheek.
"That's not what we had in mind," she told AFP. "We signed Shane because he's an international sporting icon; he's brash and he's passionate, just like us, and that's the message we want to send to our customers."
Warne, who this week was ranked the world's best bowler for the first time in 10 years, has had a mixed history with sponsors.
He accepted 200,000 dollars (148,000 US) from a nicotine gum manufacturer to give up smoking in 1999 but was snapped having a cigarette by a boy in New Zealand, who he then chased and demanded hand over his camera.
He also signed a deal to promote a hair replacement treatment earlier this year after being ribbed by teammates about his bald patch.
Warne was stripped of the Australian vice-captaincy in 2000 after he admitted bombarding a British nurse with lewd text messages after she spurned his advances in a nightclub.
The bowler's marriage disintegrated earlier this year after a series of revelations in the British tabloids detailed his alleged infidelities.
Australia's Channel Nine has cancelled his 300,000 dollar (225,000 US) television commentary contract this year because of his off-field antics.