Professor Jean-François Muller, a distinguished figure in the field of mass spectrometry, made significant contributions to the advancement of analytical chemistry and its applications. As the founding director of the Laboratory of Mass Spectrometry and Laser Chemistry at the University of Metz, Muller played a pivotal role in establishing Metz as a leading center for mass spectrometry research. His pioneering work, particularly in the development of matrix-assisted laser desorption/ionization (MALDI) instrumentation and Fourier transform ion cyclotron resonance mass Spectrometry (FTICR MS), has had a profound impact on various scientific disciplines. This article commemorates Professor Muller's illustrious career and highlights his collaborative efforts with industrial partners such as Total, which led to groundbreaking advancements in MS analysis. I will delve into the key findings of my thesis which focused on instrumental developments for MALDI analysis and imaging, as well as personal reminiscences and the impact of his inspiring mentorship.