Al Franken, the best-known host of the liberal network, announced his departure from his show today, in order to explore a run for the U.S. Senate from Minnesota.
Green is the brother of Mark Green, the New York Democrat who served as the city's public advocate in the 90s and ran for mayor against Michael Bloomberg in 2001.
He has already signed a letter of intent, and plans to finalize a purchase agreement within the week.
Air America CEO Scott Elberg confirmed the sale. "This is a great thing, for our affiliates, the company, the audience and every employee in our organization."
Green is chairman of SL Green Realty Corp, a real estate investment trust specializing in office buildings with a market cap of $12 billion.
Brother Mark is a frequent guest on Air America, and sat in for David Bender, the host of the Air America show Politically Direct, for a couple of weeks earlier this month.
When Franken leaves the network in a few weeks, he'll be replaced by Thom Hartmann, who already has a syndicated show on the network's lineup.
In Memphis, Air America can be heard on WWTQ AM-680.