Mari-Jo P. Ruiz (1943–2022) was a well-loved teacher, respected administrator, inspiring mentor, trusted colleague, caring friend, and many more. But in this paper, we highlight Mari-Jo’s work as a researcher in graph theory. From May 1980, when she defended her dissertation on rhythmic graphs until her last days in December 2022, she published more than twenty papers on various topics in graph theory. We will give a summary of her main results on different graph theory problems.