He was the grandson of Richard Bache Jr., who served in the Republic of Texas Navy and was elected as a Representative to the Second Texas Legislature in 1847, and Sophia Burrell Dallas, the daughter of Arabella Maria Smith and Alexander J. Dallas an American statesman who served as the U.S. Treasury Secretary under President James Madison.

[2][3] On the night the Maine was blown up in Havana harbor, Wainwright stood beside Sigsbee on the quarterdeck as the vessel was sinking.

From the beginning, Wainwright believed the Maine was not blown up by accident and he was impatient to avenge the death of the officers, bluejackets and Marines who died as a result.

[4] In the interval between the blowing up of the Maine and the declaration of war against Spain, Wainwright was assigned command of the tender Fern and placed in charge of the salvage survey and recovery of the bodies of the victims.

In the Battle of Santiago de Cuba he engaged the Spanish torpedo boats Furor and Plutón, driving them ashore as wrecks with her battery of 6-pounders.

[7] The victory came with no casualties, which was attributed to "The accuracy and rapidity of her fire, making the proper service of the guns on the Spanish ships impossible."

[11] In 1904 he commanded American forces during the Santo Domingo Affair in which his ships shelled rebel troops and supported an amphibious assault.

[13] He married Evelyn Wotherspoon on September 11, 1873, in Washington, D.C.. Their son, Commander Richard Wainwright, Jr., United States Navy, earned the Medal of Honor for his service at Veracruz, Mexico.