The Cowsills appeared on American Bandstand on January 23, 1971. Bill Cowsill also made a solo appearance on September 19, 1970.
Over the years various Cowsills did interviews on Dick's radio shows. Bill appeared on Rock Roll and Remember in 1991. Music Machine hosted Paul in 1974 and also 1982. John could be heard on the August 30 - September 2, 1991 version of Dick Clark's Summer Memories and Bob also did an interview in 1969 on Dick's Your Navy Presents.
Of course the most famous Cowsills/Dick Clark story is what happen in 1990 when the Cowsills were asked to be a part of Dick's Caravan of Stars. As the story goes, Bob, Paul, John and Susan were in Dick's office ready to sign the contract, when a pen could not be found. So while the pen was being found, the C's went to lunch, changed their minds, and re-dedicated themselves to creating new music.
"Hair" appears on Dick Clark's 20 Years of Rock and Roll CD set. Cowsill music was played frequently on Dick's radio shows. Last known play was his show which aired March 17-18, 2012, when "Hair" came out of the speakers.
Rest In Peace, Dick. America won't be the same.