Thanks for the follow-up on this.I think I have it pieced together, although there are some peculiarities.[aren't there always?!]I did not track Walden's name as Smith.That must have been a transcription error for 'South'.
As near as I can tell, Charles Walden was born a slave at Bowling Green, Pike County, MO about 1841-1848.As you know, many slaves did not know their precise date of birth or age.His father apparently was (white) Dr. Charles T. Walden of Bowling Green.[White] Dr. Walden was born in VA about 1813.He married Emily Crow 25 Jun 1846 in Pike County.He is shown on the 1850 slave census with two slaves, a black female age 60 and a black male age 8.In 1860 he had moved to Ashley MO (about 10 miles south).He does not list any slaves in 1860 but wife Emily does, a male age 19.After the Civil War he and wife Emily moved to the Modesto CA area where he died in 1889 and wife died in 1891.
Here I make an assumption.The mother of [black] Charles Walden was named Mary (Mariah), b about 1822 in KY.She was probably sold sometime after 1850 to John South.John South owned over 20 slaves in Pike County in 1850 but moved to Lincoln County by 1860.[Black] Charles Walden seems to have adopted his mother's surname of South when he enlisted in the Army.
[Black] Charles Walden enlisted in the 29th USCT in June 1864 as Charles South.He was engaged at the siege of Petersburg and probably fought at the Battle of the Crater.He was injured there and at Weldon.The injuries were apparently severe, as he was in Army hospital at Philadelphia July 1864 to January 1865.
After his discharge in June 1865 he returned to Pike County and was living with his mother Mariah South at Bowling Green in 1870 census. By that time he had adopted the surname of Walden.His occupation is shown as laborer.
On 1880 he appears at Bowling Green as Charles Walden, age 35, physician, married to Sallie, age 24.He apparently had picked up medical skills while a slave with [white] Dr. Walden.At that time, medical college was not required to be a physician.Wife Sallie was Salle Loyd, daughter of Humphrey and Amanda Lloyd (Loyd).They appear with Sallie on the 1870 census at Cuivre Township, Pike County.Charles and Sallie were married 12 Feb 1874 in Pike County.They apparently had one daughter Annie Mae Walden, born 1877, and one daughter Dora (Buckner), born 1882.Sallie and Charles were divorced and Sallie remarried to Joseph Pearson of Chicago.
Between that time and 1902 Charles apparently taught school in Chicago.
Charles married Lucy Taylor about 1902 and was living at Sedalia until 1914.He was admitted to the Home for Disabled Volunteer Soldiers at Milwaukee on Oct 18, 1914 and was discharged Dec 18, 1914.The record shows his residence as Chicago, a school teacher and a widower.He was discharged to the care of Dora Buckner of Chicago.Medical notation shows defective hearing and vision, and cardio problems.
comment:his Milwaukee registration obviously was in error (widower/Chicago residence) and it is possible he was in dementia at the time.
Further comment on Collins South.He was born in VA 1 Aug 1840 and died 28 Nov 1931 at Bowling Green.His father was Mitchell South.He was owned by John South of (1850) Pike County and (1860) Lincoln County.He served in the 29th Regiment USCT.His military notation says "free before April 19, 1861".He married twice, with four children.He had a son Charles W. South, but this Charles was living at Lawrence KS in 1925 and so he is not the same as Charles Walden/South.Collins South last appeared on census in 1910 at Bowling Green and divorced.