[1] His earliest memory of interest in physics dates from about age 13, when he saved the money he earned delivering newspapers to buy a book by Robert Andrews Millikan, Electrons (+And -) Protons Photons Neutrons Mesotrons and Cosmic Rays.

[2] In 1956, he married Mary Louise Ross, with whom he has five daughters: Gwendolyn Holbrow, Elizabeth, Alice, Katherine and Martha.

[1][6] He spent a sabbatical year in 1969-70 at the Stanford Linear Accelerator, and another at the California Institute of Technology in 1975-76, working in the Kellogg Radiation Laboratory.

[2] During the summer of 1975, Holbrow was a NASA-ASEE Summer Faculty Fellow at Stanford University and Ames Research Center, where he participated in a NASA project to develop colonies in space, culminating in the report Space Settlements: A Design Study,[10] and featured in an article by Isaac Asimov in the July, 1976, issue of National Geographic.

[6] Following Holbrow's retirement from Colgate University in 2003, he was a visiting professor of physics at Massachusetts Institute of Technology, where he worked on developing physics MOOCs,[15] and a visiting scholar at Harvard University, where he won an award for excellence in teaching.

[9] Holbrow was also active in the Lexington Computer and Technology Group[16] based in Lexington, Massachusetts and as a member he has given over a dozen presentations on such subjects as Quantum Mechanics/Physics,[17][18][19] Lagrangian points,[20] the greenhouse effect on Venus,[21] Arithmetics,[22] Space Colonies in Solar Orbit,[23] and the Manhattan Project.