[4] In 1963, he was recruited as a full professor and director of the clinical psychology training program for the City University of New York.

[6] To study daydreaming, Singer and co-worker John S. Antrobus of the City University of New York developed a questionnaire designed to measure the various dimensions that characterize the individual's inner life.

Singer and co-workers described the IPI: The 28 subscales of this self-report measure of ongoing thought predisposition attempt to sample various domains of mentation style (such as propensity for boredom or distractibility, rate of mentation, degree of visual or auditory imagery during daydreaming), orientation toward daydreaming more generally (for example, the degree to which an individual can become totally absorbed in fantasy activity, the degree to which daydreaming is accepted as relatively "normal and even desirable"), and specific fantasy patterns (such as sexual content, hostile-aggressive content, or fantasies of guilt).

They co-directed the Yale University Family Television Research and Consultation Center, which provided consultation to many influential children's television programs, including Mister Rogers' Neighborhood and Barney & Friends.

[4][2] From 1949 until her death in 2016, he was married to Dorothy G. Singer,[15] who was a senior research scientist in psychology at Yale.