Greer had a prominent continuing role as Reverend Alden in the NBC series "Little House on the Prairie" from 1974 to 1983. Often cast as a minister, he performed the marriages of Rob and Laura Petrie on "The Dick Van Dyke Show" and Mike and Carol Brady on "The Brady Bunch"; and from 1992 to 1996 he tended to the spiritual needs of the townfolk in fictional Rome, Wisconsin, as Reverend Henry Novotny in "Picket Fences". He also had a guest appearance on an episode of Scott Baio's "Charles in Charge" in the role of Buzz Powell.