Born in Reading, Aug. 16, 1842, Lt. Col. Dechert was the son of Elijah and Mary Williams (Porter) Dechert. Robert attended local schools, the Saunders Academy in Philadelphia, and graduated from Central High School in 1861. He studied law briefly before entering the 29th Regt., PVI, although under legal age, enlisting as Sgt. Major, Co. C, July 1, 1861. Dechert, promoted to 1st Lt. on Jan. 16, 1862, trained with the regiment before seeing first action in Winchester, Va., March 12, 1862, driving Jackson out and capturing the town in May. The regiment served as a reserve unit at the Battle of Cedar Mountain and guarded trains during First Bull Run. He served as provost and rear guard at Antietam; action at Fredericksburg and the Mud March, Chancellorsville, and Gettysburg, where he served as Acting Asst. Adj. Gen., First Division, 12th Army Corps. In southern campaigns, he participated in the reopening of the Tennessee River; Battle of Wauhatchie (Tn.); Chattanooga; Lookout Mtn.; Mission Ridge; Ringgold Gap; and Taylor’s Ridge. Dechert re-enlisted on Dec. 10, 1863; promoted to captain, Feb. 23, 1864; saw further action during the Atlanta campaign at Resaca (GA), Kennesaw Mountain, the siege and occupation of Atlanta, participated in Sherman’s march to the sea, the Carolinas campaign (promoted to major), and the surrender of Joseph Johnston’s army. He served in Washington through July 1865; awarded brevet promotion to Lt. Col.; and was mustered out on July 11, 1865.
After the war (1867), Dechert joined the Gray Reserves as Capt., Co. F. He served as Sgt., Cornet, and Commander of the (Philadelphia) City Troop in 1878. A prominent lawyer and politician, he was admitted to the bar in 1866; elected Asst. District Attorney, 1868; and as a vacancy-replacement Democrat (from a Republican district) to the state Senate in 1871, throwing the upper house majority to his party. Dechert returned as asst. D.A. in 1874 and 1880, serving as city Controller in 1884 and 1887. The senator passed away in Philadelphia, May 12, 1894.