What do the blaze of LED signs in Times Square, the rumble of construction at Lincoln Center for the Performing Arts, and an avant-garde opera where the audience gets rolled back and forth on a set of railroad tracks have in common?

Answer: Rebecca Robertson.

Ms. Robertson, who trained as an urban designer in Toronto and lived in Mexico and Venezuela before coming to New York in 1982, has already left a major mark on her adopted city — and it’s fair to say she’s not done yet. In the last 20 years, Ms. Robertson has had her hand in three major projects. From 1987 to 1997, she was the president of The 42nd Street Development Project, overseeing the revitalization of one of the most notoriously crime-ridden blocks in the city. From 2000 to 2006, she was the executive director of Lincoln Center redevelopment, spearheading a renovation plan to make the almost 50-year-old campus more youthful and welcoming.

Now, as the president and CEO of the Seventh Regiment Armory Conservancy, Ms. Robertson is leading a $200 million effort to restore the 19th-century Armory building, with the goal of turning it into a visual and performing arts center. Although the major construction won’t start until 2010, arts organizations around town are already eager to make use of the space, particularly the 55,000-square-foot Drill Hall. “We’ve been inundated with requests to do innovative, fascinating works that can’t [otherwise] come to New York,” Ms. Robertson said in a recent interview in her office at the Armory.

In March, the Armory will be filled with contemporary art installations, as part of the Whitney Biennial. In July, it will host its first opera, an avant-garde production of “Die Soldaten,” which originated at the Ruhr Triennale in Germany and is being brought to New York by the Lincoln Center Festival.

Ms. Robertson’s office reflects the way she works. Arranged neatly on a long table are a couple of dozen books on art and design, including Maya Lin’s “Systematic Landscapes,” “Creative Time: The Book: 33 Years of Public Art,” the catalog for the 2007 Venice Biennale, and a book on the Herter Brothers, the 19th-century design firm that decorated several rooms at the Armory.

“This is my source table — I’m a very visual person,” Ms. Robertson said.

Ms. Robertson said she grew up loving the “spontaneity and chaos and beauty” of cities, and, as an urban designer, she wanted to create urban landscapes that were surprising and irregular.

When she first took over the 42nd Street project, it was the opposite of that: a “very corporate plan,” she said, with large, blank office towers and a Merchandise Mart — a wholesale emporium — that would be closed to the public. Ms. Robertson’s idea was to return 42nd Street to the honky-tonk, populist spirit of the days when audiences threw fruit at the freak acts performing at Hammerstein’s Victoria Theater or visited the Flea Circus at Hubert’s Dime Museum. Through a method she described as “unplanning,” which involved dividing the block among several developers and making each tenant speak for himself, she managed to create a revitalized 42nd Street every bit as cacophonous as its earlier, seedier incarnations.

“You have to listen to the place,” Ms. Robertson said. “And by listening to the place, by making it bold and iconic, it’s good economics.”

“She really [understands] what makes New York tick,” the architect Robert A.M. Stern said of Ms. Robertson. “42nd Street is one of the few great planning stories with a happy ending in our time.”

Vincent Tese, who from 1985 to 1994 ran the Urban Development Corporation, the state body of which Ms. Robertson’s group was a subsidiary, called her “a great negotiator. Anybody who can negotiate with Disney is a great negotiator.”

It was on 42nd Street that Ms. Robertson first worked with Elizabeth Diller, whose firm, Diller Scofidio + Renfro, would later design Lincoln Center’s redevelopment plan. In the early 1990’s, the firm was one of several commissioned by Creative Time to do site-specific works on 42nd Street. Their contribution was a video in which a female mouth cooed enigmatic invitations such as, “Hey, you, wanna buy a ticket to paradise?”

At Lincoln Center, the goal was to turn the campus from a place that felt exclusive, where the focus was on what happened at 8 o’clock, into one that celebrated the artists who worked there all day. “Ten thousand people work there every day, rehearsing, sweating, designing,” Ms. Robertson said. “Young people from all over the world come to study” at Juilliard and the School of American Ballet. “It’s the most populist place in New York.”

The planning for redevelopment was long and contentious. A plan by Frank Gehry to put a glass dome over the main plaza was tossed out; executives came and went. Ms. Robertson credits Ms. Diller’s design with finally convincing the constituents to support redevelopment, but her tenacity played a role, too.

The president of Lincoln Center, Reynold Levy, described Ms. Robertson as indefatigable and completely committed to her projects. “If Rebecca fell out of bed at 3:00 in the morning, she would be entitled to workers’ compensation, because she’s always thinking about things,” Mr. Levy said. In a way, the trajectory of Ms. Robertson’s career reflects how New York itself has changed in 20 years. 42nd Street was, at its base, a clean-up project, though she turned it into something more. Although planning started during the Giuliani years, Lincoln Center redevelopment is imbued with the spirit of Mayor Bloomberg’s New York — a city of wealth and optimism, where culture is celebrated as an engine of economic activity, at the same time that arts institutions compete to be viewed as accessible and populist. By the time construction begins at the Armory, New York will have entered yet another era. And for an augury about where New York is headed, keep your ears open for news of Ms. Robertson’s next job.