Jim Wilson/The New York Times Al Gore at the Current TV studios in San Francisco in 2005. He said Al Jazeera’s coverage was “thorough, fair and informative.”

Al Gore’s Current TV was never popular with viewers, but it was a hit where it counted: with cable and satellite providers. When he co-founded the channel in 2005, Mr. Gore managed to get the channel piped into tens of millions of households — a huge number for an untested network — through a combination of personal lobbying and arm-twisting of industry giants.

He called on those skills again after deciding in December to sell Current TV to Al Jazeera for $500 million. To preserve the deal — and the estimated $100 million he would personally receive — he went to some of those same distributors, who were looking for an excuse to drop the low-rated channel, and reminded them that their contracts with Current TV called it a news channel. Were the distributors going to say that an American version of Al Jazeera didn’t qualify, possibly invoking ugly stereotypes of the Middle Eastern news giant?

“The lawyers for the carriers couldn’t find their way around it,” said a person briefed on the negotiations who described them on condition of anonymity.

Mr. Gore, who lost his last big legal argument — the one in 2000 — succeeded. On Wednesday night, a deal was announced that will bring the Al Jazeera brand into at least 40 million homes in the United States. It will also make Mr. Gore, who is already estimated to be worth more than $100 million, an even richer man.

The deal completed an eight-year odyssey for Mr. Gore and for Current TV that confirmed one of the realities of show business: it can be a lot easier to profit from a channel than to come up with must-see TV for viewers.

Television executives and observers were surprised by both the big price tag and the decision by Mr. Gore, one of the best-known proponents for action to combat global warming, to sell to a Middle Eastern monarchy built with oil wealth.

The headline on a FoxNews.com op-ed on Thursday was “Global warming guru Al Gore becomes rich hypocrite with sale of Current TV to Qatar, Inc.” Several analysts said that Al Jazeera overpaid for Current.

“The deep-pocketed Qatari royal family backing Al Jazeera handily outbid any other bidder’s rational bid,” the research firm PrivCo said in a note to clients.

Mr. Gore did not directly respond to those lines of criticism on Thursday. But in an e-mail message he wrote of his reason for divesting: “I am incredibly proud of what Current has been able to accomplish. But broadcast media is a business, and being an independent content producer in a time of increasing consolidation is a challenge.”

Current was never a full-time job for Mr. Gore. He is a co-founder of Generation Investment Management, an investment partner at the Silicon Valley venture capital firm Kleiner Perkins Caufield & Byers, an adviser to Google and a board member at Apple. He also is the chairman of a nonprofit called the Climate Reality Project. He rarely appeared on camera on Current.

Still, as its chairman, he was seen as crucial to the business.

“When it came to distribution issues, he was always available to make that final call. He was always the closer,” said a Current TV executive, who like others interviewed insisted on anonymity to protect business relationships.

Current was born out of Newsworld International, a niche channel that Mr. Gore and his business partners bought in 2004 for an undisclosed sum. Newsworld’s biggest distributor at the time was DirecTV, which sold television service to 20 million homes, and the man about to become the controlling shareholder of DirecTV was none other than Rupert Murdoch, the chief executive of News Corporation.

In a meeting in New York, Mr. Gore leaned on Mr. Murdoch for an extended contract with a lucrative per-subscriber fee.

Mr. Gore asserted that DirecTV should carry a “diverse set of news sources.”

The resulting contract guaranteed Current roughly 10 cents per subscriber per month and helped Mr. Gore secure the financing he needed to acquire Newsworld. It also laid the groundwork for similar extensions with smaller distributors.

That’s why Current, despite having one of the puniest audiences of any widely distributed cable channel, was able to post annual revenue of about $100 million.

Mr. Gore took a role in running Current, handpicking some hosts for the channel, including Keith Olbermann and Jennifer Granholm in 2011 and Mr. Olbermann’s replacement, Eliot Spitzer, in 2012. (Ms. Granholm recalled the day when “Al Gore called out of the blue and said, ‘We’ve got this network, and this is a really important election. We want to do a political show about the election — would you be interested in helping?’”)

But none of the hosts could attract an audience large enough to satisfy distributors, particularly Time Warner Cable, which had been warning for over a year that it might drop Current from its lineup. Mr. Gore, frustrated by the low ratings, told associates he felt he was having more impact through his AlGore.com blog and through volunteer training than through Current.

Last summer Mr. Gore started anchoring election coverage himself, but by then he and his co-founder Joel Hyatt were determined to cash out. In the fall, their bankers invited a phalanx of major media companies, including The New York Times Company, to look at Current’s books and took calls from interested parties, including Glenn Beck’s online network TheBlaze, which like Al Jazeera has been seeking to make deals with distributors.

The prospect of Mr. Gore’s doing business with Mr. Beck, a staunch conservative, was even more unlikely than Mr. Gore and Al Jazeera. Mr. Beck said on his radio show Thursday that his company’s interest was rebuffed “within 15 minutes.”

“We were not allowed to the table,” he said. “He didn’t sell to the highest bidder. He looked for, Who do I ideologically align with?” Mr. Beck’s producer Stu Burguiere added, “The guy who was vice president of the United States and was 537 votes away from being president during 9/11 is ideologically aligned, by his own definition, with the network that Osama bin Laden went to every time he wanted to get a message out.”

Mr. Gore, who will have an unpaid seat on the board of the new Al Jazeera channel, does not see it that way. Al Jazeera, he said, is one of the most popular media companies in the world.

“Their global reach is unmatched and their coverage of major events like the Arab Spring is thorough, fair and informative,” he said.

Patrick Healy contributed reporting.