After admission to the Virginia bar, Slayton established a practice in South Boston, interrupted by a tour of duty in the U.S. Army, but which he continued for two decades in the Virginia National Guard, serving in the Judge Advocate General Corps and rising to the rank of lieutenant colonel.

[1] Slayton first won election to the House of Delegates in 1972, and won re-election seven times (generally without opposition)[2] until 1987, when 31 year old Republican Mark Hagood thwarted his re-election bid (but would be defeated by Ted Bennett, the former Halifax County Commonwealth's attorney as well as Slayton's law partner) two years later.

After his defeat, Slayton used his legal skills to combat the redistricting following the 1990 census, which eliminated the traditional state senate district that included rural Halifax, Brunswick and Meckenburg counties (ironically held for decades by Mark Hagood's great-uncle James D. Hagood then by Howard P. Anderson), and instead associated Halifax county with urban and far more populous Portsmouth.

Then, in 1995, Slayton ran as an independent for that senate seat, but despite strength in rural portions, lost to incumbent Louise Lucas.

[1] Another legal case that cemented Slayton's reputation in his community was his representation of Riverdale, Halifax County, Virginia businesses against the U.S. Army Corps of Engineers, which led to a multi-million dollar settlement (under seal) for severe flooding of the Dan River in Riverdale, following the corps' tree planting program to limit erosion.