Andrew Frey’s biography on the Mayer Brown website says “He has argued 64 cases in the US Supreme Court, more than any other lawyer currently in private practice.”
Well, Carter Phillips of Sidley Austin has been creeping up for some time now and finally beat him when he argued for the respondents in Gross v. FBL Financial Services in March. Phillips’ online biography says that he now has 65 arguments.
By my count then, Phillips has argued the third most cases of anyone currently practicing, behind Michael Dreeben and Edwin Kneedler. What is impressive though, is that 56 of Phillips’ arguments came while he was working in private practice, possibly more than anyone else that I know of. Frey served as Deputy SG for 13 years (1973-1986) and likely amassed at least half of his current total during that time. Both Dreeben, Kneeder, and Lawrence Wallace (157 total, but retired in 2003) have argued all of their cases as members of the Office of the Solicitor General.