He was the Tisch Distinguished Professor Emeritus in Cornell University's Department of Astronomy, which he chaired between 1979 and 1999.

[1] Between 1965 and 1967 Terzian worked as a research associate at the newly built Arecibo Observatory in Puerto Rico, managed by Cornell University.

[2] Jonathan I. Lunine, the David C. Duncan Professor in the Physical Sciences at Cornell, stated that Terzian's "legacy as a department chair and colleague is profound and lasting.

"[1] Frank H. T. Rhodes, President of Cornell in 1977–1995, stated that "He presided over a remarkable department, full of wonderful colleagues — Carl Sagan, Tommy Gold, Ed Salpeter … and somehow the wisdom and sheer sense of partnership that Yervant brought to that distinguished group was something that not only kept the department intact, but allowed it to grow.

[4] Between 1996 and 2015 Terzian was the director of the NASA New York Space Grant Consortium at Cornell, which aimed to enhance science education.

[1][2] Terzian was involved in planning to construct the Square Kilometer Array (SKA) giant radio telescope.

[2][10] Terzian's research focused on the physics of the interstellar medium, galaxies, and radio astronomy.

[2] He studied the physics of the stellar evolution, planetary nebulae, hydrogen gas between galaxies and the presence of unseen matter in intergalactic space.

[12] His second wife was Patricia E. Fernandez de Castro Martinez,[1][5] an editor at the Department of Astronomy at Cornell[13] and president of the Latino Civic Association of Tompkins County.