With that, the network entered the cable news fray long dominated by CNN, MSNBC and Fox News Channel.
The Qatar-based Al-Jazeera Media Network launched its U.S. outlet only eight months after announcing the new venture, which replaced Al Gore's Current TV in more than 45 million TV homes Tuesday.
An hour before settling into its regular schedule at 4 p.m. Eastern time, the network aired a prerecorded preview of its programming and goals.
"We are here to tell the story the way it happens, as it happens," anchor Antonio Mora said as the preview began.
At the same time, the Al-Jazeera English network was suspended. It had been available since 2006 online and in a scattering of cable systems.
Headquartered in New York, Al-Jazeera America has vowed to provide unbiased, in-depth domestic and global news. It aims to strike a contrast to the "news talk" often favoured by its Big Three competitors. (Its promotional tagline: "There's more to it.")
It has hired a number of veterans of U.S. television, including Harris, a CNN alum, and Mora, previously at ABC News. Other familiar faces include Sheila MacVicar (formerly of CBS News), Soledad O'Brien (NBC News and CNN), Joie Chen (CNN and CBS News) and John Seigenthaler (NBC News).
Scheduled programs include a nightly newscast anchored by Seigenthaler; "Consider This," a current-affairs hour hosted by Mora; "America Tonight," a newsmagazine described as the network's flagship telecast anchored by Chen; and "Real Money" with former CNN business correspondent Ali Velshi.
Besides New York, domestic bureaus are in Washington, Los Angeles, San Francisco, Dallas, Detroit, Chicago, Denver, Miami, Seattle, New Orleans and Nashville, Tenn.
The new network also will draw from the 70 bureaus parent Al-Jazeera operates globally.
Al-Jazeera Media claimed an instant U.S. foothold with its $500 million purchase of Current TV and the cable distribution of that little-watched network. Al-Jazeera America also is available from satellite providers DirecTV and Dish Network.
The breakneck pace of getting the network on the air rivals that of Fox News Channel, which was announced in November 1995 and signed on the following October. MSNBC had launched three months earlier. Before that, CNN, which pioneered the cable news format with its debut in 1980, had the field to itself.
Thanks to the deep pockets of its parent, Al-Jazeera America commands considerable resources with no urgent need to turn a profit, as evidenced by a stated policy to air just six minutes of commercials each hour, less than half the usual time devoted to advertising by most commercial networks.
But the channel also has challenges ahead. It will have to win over viewers to the serious newscasting it promises to deliver and overcome suspicion some Americans may feel for a news organization controlled by a foreign government or even see as anti-American.
Meanwhile, the network wasted no time demonstrating it will jump on hot-button issues, and make certain assumptions, that might turn off a portion of the public.
At 5 p.m. Eastern, on the first "Inside Story" discussion program, host Libby Casey, formerly of C-SPAN, led a thoughtful half-hour with a trio of experts exploring the threat of climate change to the U.S. No one present said its dangers don't exist.
Al-Jazeera America: http://america.aljazeera.com