Stimulated by a question asked of me by a leading general counsel, I researched the differences between the titles “General Counsel” and “Chief Legal Officer.” Some posts here offered background (See my post of March 23, 2005: title expansion and more frequent appearance of CLO; March 22, 2006: differentiates “general counsel” and “chief legal officer”; May 4, 2007: European counterparts as “Head of legal” and “Legal Director; and Dec. 5, 2011: post on this blog with the most number of visits was about the distinction.).
The CLO title is definitely of more recent vintage and is also less frequent than the GC title. Data to support this belief is not known to me, but that is the impression I have from consulting, reading and my posts here (See my post of Dec. 31, 2007: Wikipedia entries for CLO and GC; Jan. 19, 2008: LinkedIn search found “general counsel” had more than 500 profiles while “chief legal officer” had 106; and Oct. 12, 2009: can only persons with bar licenses in the US be “general counsel”.).
Where the title is bestowed, it seems to be higher ranking, with more corporate muscle, than “general counsel” (See my post of Nov. 6, 2007: CLOs get more equity awards than GCs; and April 24, 2009: salary differences between CLO and GC positions.).