[1] During the early part of his military career, Reynolds spent much of his time aboard various vessels in the Revenue Cutter Service and its successor agency, the United States Coast Guard.

He took an active interest in the education of officers as superintendent of the Revenue Cutter Service School of Instruction by increasing and modernizing the curriculum.

[1] He was appointed at age eighteen as a cadet to the Revenue Cutter Service School of Instruction at Curtis Bay, Maryland, on 24 May 1878 and after two years training was commissioned as a third lieutenant on 17 July 1880.

As a member of the crew of USRC Corwin, in 1881, he participated in the search for the missing exploration steamer USS Jeannette along the northern coast of Siberia using a sled team.

[7] At the beginning of the Spanish–American War, Reynolds was serving as captain of the USRC Louis McLane in the North Atlantic Fleet under Navy Rear Admiral William T. Sampson.

[9] On 23 January 1909, as captain of USRC Seneca, he responded to the collision of White Star passenger liner SS Republic with the Italian liner SS Florida, 26 miles southeast of Nantucket, Massachusetts, assisting USRC Gresham with the rescue of passengers and crew of the Republic.

[20] The legislation was ultimately defeated through the efforts of the recently retired Bertholf, who had many political connections and Glass, who had resigned his Treasury position to accept appointment as Senator from Virginia.

Most of the enlistments in the Coast Guard made during World War I were voluntary and most of the men wanted discharged from the service as soon as possible.

Efforts to replace discharged personnel were not very successful even with the offer of one year enlistments and greatly increased recruiting activity.

Because the enlisted Coast Guardsmen could only be held in service for three months after a formal peace treaty was signed with Germany, many of them felt they were being unfairly treated.

[21] A shortage of officers occurred post war despite a law requiring the Coast Guard to adopt the Navy's rank structure.

Reynolds attempted to reduce the shortage of officers by asking the Navy to allow some of their new graduates from the Naval Academy to transfer to the Coast Guard.

With the passage of the Eighteenth Amendment to the United States Constitution and the enabling law known as the Volstead Act, the enforcement of national prohibition after 16 January 1920 fell to the Treasury Department's Bureau of Internal Revenue.

[25] Reynolds requested in his 1923 budget proposals an increase in personnel manning levels of 3,535 officers and men and the acquisition of twenty new cutters, 200 cabin cruisers, and 91 motorboats[26] Congress thought the request was excessive, but did fund twenty destroyers and two minesweepers as well as 223 cabin cruisers, and 100 smaller motorboats with an additional 4,356 officers and men to operate the vessels.

[26] On 12 January 1923, by act of Congress, Reynolds became the first Coast Guard officer to hold the rank of Rear Admiral.