The ratings for the Sunday premiere of HBO’s prohibition era extravaganza Boardwalk Empire were barely in this morning when the pay cable network announced a second-season pickup for the drama from Martin Scorsese and Terence Winter. HBO made the decision “following resounding critical approval and high viewer numbers”, it said. The series starring Steve Buscemi debuted with 4.8 million viewers to become HBO’s most watched series premiere since the 2004 opener of Deadwood behind The Sopranos. (I feel that is only appropriate because there are similarities in the tone between Boardwalk and Deadwood.) Because of HBO’s big investment in building elaborate sets for Boardwalk, including an actual boardwalk, a second season renewal was always considered a given as networks look to amortize upfront costs. Still, the overwhelmingly positive reviews and solid premiere ratings probably sealed the deal. Here is HBO’s release:

LOS ANGELES, Sept. 21, 2010 – Following resounding critical approval and high viewer numbers for the series’ Sept. 19 debut, HBO has renewed BOARDWALK EMPIRE for a second season, it was announced today by Michael Lombardo, president, HBO Programming.

“All the ingredients aligned for this one, from Mark Wahlberg and Steve Levinson’s initial pitch, to Martin Scorsese’s enormous contributions as director and executive producer, to the genius of Terry Winter and the expertise of Tim Van Patten, to a stellar cast led by Steve Buscemi,” said Lombardo. “The response from the media and our viewers has been nothing short of amazing.”

From Terence Winter, and Martin Scorsese, BOARDWALK EMPIRE is set in Atlantic City at the dawn of Prohibition, when the sale of alcohol became illegal throughout the United States.

The Sept. 19 premiere of BOARDWALK EMPIRE averaged 4.8 million viewers during the 9:00 p.m. airing to score HBO’s largest premiere of any program in over six years (since March 21, 2004 – “Deadwood” with “The Sopranos” as lead-in). With additional plays at 10:15 p.m. and 11:30 p.m., BOARDWALK EMPIRE was watched by a combined 7.1 million viewers for the night.

Season one credits: Created by Terence Winter, BOARDWALK EMPIRE is executive produced by Terence Winter, Martin Scorsese, Tim Van Patten, Stephen Levinson and Mark Wahlberg; co-executive producers, Gene Kelly and Lawrence Konner; producers (series), Rudd Simmons and Rick Yorn; producer (pilot), David Coatsworth; supervising producers, Howard Korder and Margaret Nagle.