McGinnis served aboard the U.S.S. Potomac and U.S.S. Owasco . Since the Owasco was at the Pensacola Navy Yard undergoing repairs that would last until October 1864, McGinnis went with a number of his shipmates to augment the Tecumseh's complement for the impending Battle of Mobile Bay after a number of her crew were sent ashore sick. 
McGinnis was aboard the Tecumseh during the Battle of Mobile Bay and survived the sinking by swimming ashore where he was captured by confederates at Fort Morgan. Per RADM Farragut's report and a statement in McGinnis' survivor's pension, McGinnis along with the other Tecumseh survivors who swam ashore instead of being rescued by the U.S.S. Metacomet crew or the Tecumseh's own cutter were sent to Andersonville Prison. , 
McGinnis was initally presumed to have died in the sinking of the Tecumseh by his family per an application his mother made for and later withdrew for his survivor's pension, but was happily surprised when McGinnis came home.  He was the only survivor of the thirteen Owasco sailors who joined the Tecumseh's crew.
McGinnis died 20 April 1883 at the age of 40. 
IntermentHoly Cross Cemetery, Brooklyn, New York (Section: Singles, Row: 8, Plot: 99)
Awards & Memorials
Alternate Spellings of Name
References and Sources Return of the United States Naval Rendezvous, New York, New York, for the week ending August 10, 1861
 NARA T1099. An index to rendezvous reports during the Civil War, 1861-1865.
 "Various Naval Matters" Army and Navy Journal, August 27, 1864 p13
 "Report of Rear-Admiral Farragut, U.S. Navy, Regarding Captured Members of the U.S.S. Tecumseh's Crew." United States House of Representatives: Official Records of the Union and Confederate Navies in the War of the Rebellion: Series I, Volume 21 West Gulf Blockading Squadron from January 1 to December 31, 1864, Government Printing Office, 1906. p.493
 "OUR BLOCKADING SQUADRONS.; Particulars of the Capture of the Lucy and the Annie off Wilmington; Captures Reported by Admiral Farragut; Safety of Four of the Tecumseh's Crew; Expedition to St. Andrew's Bay, Florida." New York Times, November 8, 1864
 Case Files of Approved Pension Applications of Widows and Other Dependents of Civil War and Later Navy Veterans ("Navy Widows' Certificates"), 1861-1910