Moldenke was the son of
Charles E. and Sophia (Heins) Moldenke. His father was a noted Egyptologist whose translation of the hieroglyphics on
Cleopatra's Needle he reprinted. Harold was born in
Watchung, New Jersey, in 1909, and earned a
bachelor's degree from
Susquehanna University in 1929. Moldenke's career started at the
New York Botanical Garden, a place he maintained a close relationship with (donating many educational materials to its library). There, he worked as a Research Fellow and part-time assistant in 1929. He taught a course in
Systematic Botany for gardeners there as well. For 16 years, he worked as the assistant and associate curator under
Henry A. Gleason. When Moldenke served in the
Civilian Public Service,
Soil Conservation Service and as a hospital attendant in
Warren, Pennsylvania, he wrote a number of papers on
Amazonian curare-producing plants with
B.A. Krukoff. These were entitled
Plants Strategic to the War Effort. His herbarium is accommodated in the Moldenke Room at the
Plant Resources Center. ==Later career==