He earned his doctorate in Medicine in 1906, with his thesis titled "Aspectos Cirúrgicos das Pancreatites Crónicas" ("Surgical Aspects of Chronic Pancreatitis"), after which he started teaching.

[3] In 1910, he oversaw a free course of Urology in Desterro Hospital, where he presented urorhythmography, using a device of his own making to "graphically register the value and rhythm of renal excretion as well as the function of the ureters".

[3] Reynaldo dos Santos was equally as accomplished and recognised for his avocation in the Fine Arts; the interest in the history of art was born while he was still a student holidaying in Figueira da Foz: he became interested in the archeological campaigns promoted by António Santos Rocha, and Rocha recommended he read the works of Hippolyte Taine.

[1] In 1915, Reynaldo dos Santos, along with José de Figueiredo, discovered a set of tapestries depicting the Portuguese conquest of the Moroccan cities of Asilah and Tangiers in 1471 in the small town of Pastrana, in Spain.

His main interests include the Manueline style — in 1922, he identified Francisco de Arruda as the architect of the iconic Belém Tower.