The son of Gortzius Geldorp, he was trained and active as a painter in Cologne before being admitted Master in the Guild of St Luke in Antwerp in 1610. Two years later his first wife Margriet Parmentiers died in Antwerp. In 1623, he moved to London where he painted a number of portraits in the Anglo-Netherlandish style, notably William Cecil, 2nd Earl of Salisbury and his wife Catherine in 1626 in Hatfield House, Hertfordshire and Sir Arthur Ingram in late 1638/early 1639. His work was generally less accomplished and his portraits more stiffly articulated than works of similar painters such as Daniel Mijtens.
According to Houbraken, he was known to the artist biographer Joachim von Sandrart who wrote that he was not a very good draughtsman and had the habit of tracing other's sketches, and then pricking holes in these sketches, and sponging this onto the canvas as a guide to paint his subjects. Houbraken disapproved of this practise, and preferred to write about painters who were good draughtsman.
- George Geldorp in the RKD
- "History - Family Portraits". Leeds City Council. Retrieved July 20, 2010.
- Art Encyclopedia. The Concise Grove Dictionary of Art. Oxford University Press, Inc. 2002.
- (Dutch) Gelsdorf biography in De groote schouburgh der Nederlantsche konstschilders en schilderessen (1718) by Arnold Houbraken, courtesy of the Digital library for Dutch literature