Smith, dual-registered with Skrill National side Welling United, has featured a number of times for the u21s this season and delivered some outstanding performances that have caught the attention of senior clubs.
After a formal approach from Leatherhead and with options limited for staking a claim in Ryan Kirby's plans the young midfielder has decided to join the Surrey outfit, currently sitting second in the league.
We wish Ollie the very best for the future.