Appointed senior children's librarian in the 1970s. Children's and youth adviser to Stockholm Public Library/Cultural Services since 1990. At the present Manager for the International Library in Stockholm. Former head of the "Stockholm Year of Reading", a citywide project intended to encourage reading among all age groups and to develop new working methods to promote reading.

Committee member of IBBY Sweden (International Board on Books for Young People) since 1997 and editor of the IBBY Sweden newsletter. Formerly a member of the jury of the major Swedish literary award the August Prize and on the board of the Swedish Institute for Children's Books (SBI). Past member of the Swedish National Council for Cultural Affairs' working group on support for children's and youth fiction and comics. For much of the 1990s, Larry Lempert was a committee member of IFLA's (International Federation of Library Associations) children's literature section.

Larry Lempert has delivered lectures and presentations on children's libraries and literature in Sweden to seminars and conferences for authors, librarians and researchers worldwide. He regards libraries as meeting places for people and new ideas, and library work as a way of encouraging reading and stimulating imagination and knowledge.