The Dutchman succeeds Mauricio Pochettino, now with Tottenham, at St Mary's.
"I think it's a cracking appointment," Le Tissier told the Saints website.
"It was a big blow for the club losing the manager and three players because everybody starts to panic, but a couple of those players have been replaced and hopefully they'll start well to fill the big boots that Adam and Rickie left.
"With Ronald coming in, he's a fantastic name in world football and should attract good players to this football club and that's probably one of the most important factors."
For the big stories and the banter follow us on Twitter: @tribalfootball