Secretary Sebelius will soon be stepping down as head of the U.S. Department of Health and Human Services. She led the agency through an extraordinary time of health system transformation. One person who knew she would be up to the job – and who knows she’s a tough act to follow – is her former insurance commissioner colleague, Sally McCarty. In this post, Sally looks back at her two decades of working with Sebelius and celebrates the tenure of a remarkable Secretary.