Together with Joseph Paxton and Edward Milner, Kemp became one of the leaders in the design of parks and gardens during the mid-Victorian era in England.
By the summer of 1845 Paxton's work was more or less complete, and he recommended to the Commissioners that Kemp be retained as superintendent and to be provided with a residence; this was accepted.
[2] In September 1845 Kemp took leave of absence to marry Sophia, daughter of Henry Bailey who had been park steward and gardener to the Spencer family at Althorp House.
However Kemp negotiated a settlement that he should work for no salary, but remain in his residence at Italian Lodge plus be given a small plot of land for him to cultivate for his needs.
The following year he worked with the architect Charles Verelst to design the garden at Stanacres (now Thornton Court) in Raby.
In 1858 a second edition of his book was published (now entitled How to Lay Out a Garden) and, although he was still working for the park, the Commissioners reviewed the agreement to provide him with free accommodation.