The District 28 state senate seat is now vacant.
Senator Robert Duncan resigned from his post effective immediately, and will start his new job as Texas Tech Chancellor on Monday.
He was named sole finalist for the position in May.
Duncan has served in the Texas senate since 1997 and is considered perhaps the state's most effective legislator.
He posted this message on his Facebook page:
"Effective today (Thursday), I will resign as a member of the Texas senate where i have had the privilege of representing the constituents of District 28 for more than 17 years. Serving in the senate and representing West Texas was a fulfilling and rewarding experience."
"I wish to thank my constituents, who allowed me to work on their behalf; my staff, who have loyally served the district; and my colleagues in the Texas legislature, with whom i have had the distinct honor to serve in both the house and senate. God bless Texas!"
Governor Perry will decide if and when to hold a special election to fill the remainder of Duncan's term.