This conversation with mitochondrial biologist Navdeep S. Chandel (Northwestern University) is part of Cold Spring Harbor Laboratory’s “Leading Strand”—CSHL’s official interview series that accompanies its world-renowned Meetings & Courses programs. In this installment, recorded for the 89th Cold Spring Harbor Laboratory Symposium on Quantitative Biology: Senescence & Aging, Chandel discusses how mitochondria function not only as energy producers but as signal-generating organelles that shape cell fate, stress responses, and disease biology. The interview is conducted by Melina Casadio (Nature Structural & Molecular Biology) and published through CSHL’s Leading Strand channel.