The bogey-free 62 equaled Palmer's lowest round on the PGA Tour.
Palmer and longtime caddie James Edmondson are full dues-paying members at Colonial. Edmondson is even the reigning club champion, winning the title for the third time last year.
Graham DeLaet, wearing pants with a plaid design similar to the jacket Colonial winners get, matched Morgan Hoffmann, David Hearn and John Peterson at 64. Matt Kuchar, No. 13 in the world ranking and the highest-ranked player in the 136-man invitational field, was in a group of six at 65.
Defending Colonial champ Zach Johnson had an opening 69.
