He was born in Chicago, and received his medical training at a homeopathic institute: the Hahnemann Medical College of Chicago.
It was there that Grubbe assembled the first x-ray machine in Chicago in 1896, and that same year, used it to treat a woman with recurrent carcinoma of the breast.
He assembled the machine and began to use it in treatments less than a year after Wilhelm Röntgen announced his discovery of the x-ray.
By 1960, Grubbe had instructed over 7000 other doctors in the medical use of x-rays.
In the course of his lifetime, he underwent more than 90 operations for multiple cancers caused by his intense, ongoing exposure to radiation, a disease from which he died.
Honors were bestowed upon Grubbe by numerous institutions, including the American Cancer Society.
He was also a fellow of the American College of Physicians.
Grubbe left money in his will to the Chicago Radiological Society to fund the Grubbe Memorial Award.