Although not an original member Bill Zorn also did a stint with the Christies. To quote from his biog on the Kingston Trio website:

In February 1970 both Pete [Zorn] and I became New Christy Minstrels after auditioning on the telephone for Sid Garris; I became musical director in May 1970 and leader later that year. We toured in the USA and internationally - virtually non-stop for four years. When I left, I had been the group's longest serving leader and had done the longest non-stop stretch of any member.

English audiences may remember him as being part of The Arizona Smoke Revue in the 70s and 80s alongside his brother Pete, Paul Downes, Phil Beer and, occasionally, Steve Knightley.

His further adventures on these shores can be found here:   http://www.kingstontrio.com/html/bill_zorn.htm