Through his research on the neurology and behavior of Drosophila melanogaster, Hall uncovered essential mechanisms of the circadian clocks and shed light on the foundations for sexual differentiation in the nervous system.

[4][5] Jeffrey Hall was born in Brooklyn, New York, and raised in the suburbs of Washington D.C., while his father worked as a reporter for the Associated Press, covering the U.S. Senate.

Hall worked with Sandler on analyzing age-dependent enzyme changes in Drosophila, with a concentration on the genetic control of chromosome behavior in meiosis.

Hershel Roman encouraged Hall to pursue postdoctoral work with Seymour Benzer, a pioneer in forward genetics, at the California Institute of Technology.

When conducting his research on this particular topic, Hall faced skepticism when trying to establish the importance of a sequence of amino acids he isolated.

Hall believed the focus should be on the individual's research; funding should not be a limiting factor on the scientist, but instead give them the flexibility to pursue new interests and hypotheses.

Hall expressed that he loves his research and flies, yet feels that the bureaucracy involved in the process prevented him from excelling and making new strides in the field.

[3] In the late 1970s, through a collaborative work with Florian von Schilcher, Hall successfully identified the nervous system regions in Drosophila that contributed to the regulation of male's courtship songs.

In the subsequent research with a postdoctoral fellow in his lab, Bambos Kyriacou, Hall discovered that Drosophila courtship song was produced rhythmically with a normal period of about one minute.

[12] In 1990, while in collaboration with Michael Rosbash and Paul Hardin, Hall discovered that the Period protein (PER) played a role in suppressing its own transcription.

While the exact role of PER was unknown, Hall, Rosbash, and Hardin were able to develop a negative transcription-translation feedback loop model (TTFL) that serves as a central mechanism of the circadian clock in Drosophila.

He found that the pigment dispersing factor protein (PDF) helps control the circadian rhythms, and in turn locomotor activity, of these genes in cells.

From this data, Hall concluded the sLNvs serve as the primary oscillator in Drosophila and PDF allows for synchrony between cells.

Upon dimerizing, the two proteins bind to the E box promoter element of the two genes via the bHLH domain to induce expression of per and tim mRNA.