1874 as a new sport, a variation of racket tennis suitable for English grounds; the thing itself is at least as old as Elizabethan times. See lawn (n.1) + tennis (n.).
Some early references seem to be to badminton, also new in 1874. By the end of the decade lawn tennis was a leading recreation in schools.
Lawn Tennis seems to be vying with Foot Ball for popularity this fall. Three clubs have been formed since the beginning of the term. ["The Brunonian," Brown University, Oct. 18, 1879]
Its popularity in English schools provoked debate.
Whether it should be desirable that lawn-tennis should supersede cricket as the principal game in the summer months, I leave to your readers to decide ; my experience teaches me that those who "go in" entirely for the former, turn out for the most part effeminate and contemptible. [from letter to the editor of "The Norvicensian," Norwich School, April 1879]
There are, as "Prudens" justly remarks, a large number of "loafers" who don't play cricket and won't join the "rifle corps." Might not a large proportion of these be induced to forsake "loafing" for the superior attractions of lawn tennis? [from letter to the editor of "The Cliftonian," Clifton College, July 1876]