Ariail served in private practice from 1974-1997 as a partner in the firm of Mitchell and Ariail, specializing in civil law and trial work. During that same time frame he was also employed as a part-time assistant solicitor with the Thirteenth Judicial Circuit handling exclusively the prosecution of murder, armed robbery and other serious felony charges.

Governor David Beasley appointed Ariail to the position of Solicitor of the Thirteenth Judicial Circuit in July 1997 to complete the term of Joe Watson. The appointment was confirmed in January 1998 by the South Carolina Senate. Ariail was then elected Solicitor of the Thirteenth Judicial Circuit on November 3, 1998.

Robert Ariail has received numerous awards and honors, including the appointment by Governor David Beasley in August 1997 to the South Carolina Commission on Prosecution Coordination and in March 1999 he received the Greenville County Sheriff's Award.

He is a member of the SC Trial Lawyers Association, the SC Solicitors' Association, the National District Attorneys' Association, the SC Bar, and the Greenville County Bar.

His civic activities include Member, Board of Trustees, Buncombe Street United Methodist Church; 2001 National Annual Fund Chairman for Wofford College; 1997 Greenville Area Chairman, Capital Campaign for Wofford College; Board member, Davidson College Athletic Foundation, 1994-1996. He is also a member of the Wofford Terrier Club.