A year ago, Jake Gyllenhaal made his professional musical theater debut as the nebbish Seymour in a concert production of “Little Shop of Horrors” at City Center, surprising those who were unaware that he had a legit singing voice. This week, he has gone a step further, tackling the lead role in “Sunday in the Park with George,” one of Stephen Sondheim’s most vocally challenging and intellectually stimulating musicals. And once again, Gyllenhaal has pulled it off, leading us to wonder what else he can do.

This production of “Sunday,” which is also being done in concert form, served as the centerpiece of City Center’s annual gala on Monday night. But due to popular demand, City Center added three additional performances of “Sunday” through Wednesday night.

Joining Gyllenhaal is Tony winner Annaleigh Ashford, who shined in the recent Broadway revivals of “You Can’t Take It With You” and “Sylvia,” and was featured in last week’s regrettable TV remake of “The Rocky Horror Picture Show.”

The supporting roles are filled out with superb Broadway talent including Phylicia Rashad (who took over for Bernadette Peters in Sondheim’s “Into the Woods”), Zachary Levi (“She Loves Me”), Phillip Boykin (“Porgy and Bess”), Carmen Cusack (“Bright Star”), Gabriel Ebert (“Matilda”), Claybourne Elder (“Bonnie and Clyde”), Lisa Howard (“Spelling Bee”) Ruthie Ann Miles (“The King and I”), Gabriella Pizzolo (“Fun Home”) and Lauren Worsham (“A Gentleman’s Guide to Love & Murder”).

“Sunday,” which won the 1985 Pulitzer Prize for Drama, begins with a portrait of the late 19th century French pointillist painter Georges Seurat (Gyllenhaal) as he ignores his mistress Dot (Ashford) and everyone else around him to fixate on the creation of what will be his initially misunderstood masterpiece, “A Sunday Afternoon on the Island of La Grande Jatte.”

The second act, set a century later, observes Seurat’s great grandson (Gyllenhaal), also named George, and his grandmother Marie (Ashford), who is Dot’s daughter. This 20th century George is a technologically-savvy contemporary artist who is in serious need of inspiration and a new artistic vision.

As directed by Sarna Lapine (niece of James Lapine, the musical’s book-writer and original director), this version of “Sunday” accentuates the score (performed by an excellent 13-piece orchestra, just slightly larger than the original Broadway production) and book (which is performed in full).

Compared to most City Center Encores! productions (which purport to be concerts but are really closer to full-scale renderings), this truly is a concert with limited staging and scripts in hand, supplemented by some visual projections on a rear screen. Because “Sunday” depends heavily on precise visual effects (including bits and pieces of the original painting in act one, plus a moving laser sculpture in act two), this concert production does lack some impact, but that is understandable under the circumstances, and it is more than made up for by the quality of the performances.

Whereas the 19th century George (originally played by Mandy Patinkin) is typically portrayed as unapologetically cold, Gyllenhaal lends a softer, sadder side to the character, even as he is obsessively at work. Likewise, his 20th century George is unusually sympathetic and even likable. One can’t help but wonder what else Gyllenhaal could do with the part if he were to commit to a Broadway revival (which is unlikely but probably not impossible).

Ashford, with her pristine comic instincts and big voice, gives a knockout, emotionally revealing performance in a role that continues to be defined by Bernadette Peters’ original performance.

Because of the intellectual and elusive nature of “Sunday,” it is a piece of theater that demands multiple viewings. Personally, I have watched the video recording of the original production dozens of times and seen several professional revivals, and I still find myself trying to gasp the meaning and intent of different parts of the score and book. Many thanks to City Center and company for providing another opportunity to wrestle with it.