A distinguishing hallmark of John’s work was his masterful ability to combine novel neuroimaging techniques, machine learning, genetics, treatment studies and clinical outcomes to advance our understanding of neurodevelopmental psychopathology. His had a profound talent for probing the neurofunctional features that underlie symptoms and often did so transdiagnostically. Beyond this, he brought clarity to the way in which we clinically approach psychiatric disorders and how we understand the complex ways in which symptoms overlap. In a field where the lines between disorders are often blurry, John’s work illuminated our understanding of specific symptoms and disorders and provided the context for clarifying neurophysiology. John had the unique ability to simultaneously see the big picture of a scientific problem and recite the intricate details of specific brain regions, subregions, or genes. When confronted with a complex problem or a finding that seemed counter to prevailing beliefs, he would wrestle with it and then fit this finding into understanding the illness, often offering a new perspective on how we see myriad neuropathologic processes. His vast knowledge and intellect were astonishing to all who had the good fortune to know him.