Antonio Giraldez studied chemistry and molecular biology at the University of Cadiz and the University Autonoma of Madrid. During his undergraduate degree, he worked with Gines Morata at the Centro de Biología Molecular in Madrid. Giraldez did his Ph.D. with Stephen Cohen at the European Molecular Biology Laboratory (Heidelberg) (1998–2002) and a postdoc with Alex Schier at the Skirball Institute (New York University) and Harvard University (2003–2006).

Giraldez established his laboratory at Yale in 2007, where he investigates the regulatory codes that shape gene expression during embryonic development. He was director of graduate studies (2012–2016) and is currently chair of the Genetics Department. The Giraldez laboratory studies the gene regulatory networks that control vertebrate development using zebra fish as a model system. Initially focused on the function of microRNAs in development, the Giraldez lab has uncovered conserved principles in the microRNA pathway, including the identification of a novel microRNA (miRNA) family (miR-430) that regulates the maternal-to-zygotic transition, the identification of deadenylation as one of the molecular mechanisms that mediate miRNA-mediated repression, the regulation of the transforming growth factor beta (TGFß) signaling by miRNAs and the identification of a novel miRNA processing pathway independent of Dicer function.

Recently, the Giraldez lab has used zebra-fish models and chemo-behavioral fingerprinting to understand how disrupting development can lead to human disorders and identify therapeutic drugs. In a CNTNAP2 mutant line, his lab performed behavioral profiling and has identified estrogenic compounds in chemical suppressor screenings, suggesting that estrogens serve as modifiers of excitatory-inhibitory circuits, dampening the adverse effects of loss of an autism risk gene during brain development. The Giraldez lab has also developed molecular and genomic tools for developmental biology, including characterizing the molecular features that influence single-guide RNA (sgRNA) stability, activity and loading into CRISPR associated protein 9 (Cas9) in vivo and developing a novel high-throughput RNA-element selection assay (RESA) to identify RNA regulatory elements.