After his season at St. Catharine, Tyndall got his first NCAA Division I coaching position as an assistant at LSU under John Brady, a position he would hold from 1997 to 2001. Tyndall helped LSU finish first in the SEC West Division in the 1999–00 season and make the Sweet 16 round of the 2000 NCAA Tournament. This LSU team also featured Stromile Swift, the #2 pick in the 2000 NBA draft.