For almost 30 years, Leila Heller ran her gallery from the Upper East Side, making a name for herself as an art dealer and for her support of emerging and midcareer Middle Eastern artists, before setting up shop in 2010 on a gallery-lined stretch of West 25th Street.

Now, Ms. Heller is returning uptown with a 16,000-square-foot, six-floor space in Midtown Manhattan that she will operate in addition to the Chelsea location. The new gallery will open on Tuesday, with an inaugural exhibition on portraiture that will run through August.