Glascock was born about 1787 in Baltinglass, County Wicklow, and joined the navy in January 1800, serving aboard the frigate HMS Glenmore under Captain George Duff.

Glascock spent the next few years with Duff seeing service in the Baltic, off the coast of Ireland and in the West Indies.

[citation needed] Glascock continued in the Douro, as senior officer, for nearly a year, during which time his conduct under troublesome and often difficult circumstances won for him the approval of the Admiralty and promotion to post-rank, on 3 June 1833, accompanied by a special and complimentary letter from Sir James Graham, the first lord.

From April 1843 to January 1847 he commanded the frigate HMS Tyne on the Mediterranean station, and during the following months was employed in Ireland as an inspector under the Poor Relief Act.

[citation needed] Glascock devoted the long intervals of half-pay, both as commander and captain, to writing, and produced several volumes of naval novels, anecdotes, reminiscences, and reflections.

Glascock wrote a two-volume work, The Naval Sketch Book, or The Service Afloat and Ashore, published in 1826.