When Paar returned to television in 1973 and was confronted by unexpected low ratings, he engaged Douglas to contribute monologue material by mail.
Douglas and his third wife Reiko (née Hashimoto), a Japanese-born singer and comedian, were regular guests on shows hosted by Merv Griffin, Dick Cavett and Johnny Carson.
By 1959, Douglas' appearances with Paar gave him a huge audience for his humorous memoirs, published by Dutton and Putnam with many mass market paperback editions by Pocket Books and others.
Some of his books, including Shut Up and Eat Your Snowshoes (1970), were set in Northern Ontario, where Jack and Reiko Douglas lived for several years after purchasing a wilderness lodge on Bird Lake near Killarney Provincial Park in 1968.
The book The Neighbors Are Scaring My Wolf (1968) was based on his experiences living in New Canaan, Connecticut, while Benedict Arnold Slept Here (1975) recalled the misadventures of the couple while operating their own inn.