Tunisia's first parliament since the 2011 revolution on Thursday elected veteran politician Mohamed Ennaceur, 80, of anti-Islamist party Nidaa Tounes as house speaker.
Ennaceur, the sole candidate, won 174 votes from the 214 MPs in attendance.
In a brief speech, he thanked lawmakers and vowed parliament would follow a consensual approach to guarantee "freedoms and human rights" and strive "to build a state of law".
The vote had initially been expected on Tuesday during the newly elected parliament's inaugural session but was delayed for consultations on a consensus candidate.
Ennaceur is deputy leader of Nidaa Tounes, which won a landmark legislative election in October -- the first since the overthrow of long-time strongman Zine El Abidine Ben Ali nearly four years ago.
Nidaa Tounes head Beji Caid Essebsi, 88, is frontrunner in a presidential election runoff due to be contested by the end of this month.
Ennaceur served as social affairs minister under Habib Bourguiba, Tunisia's "father of independence", during the 1970s and 1980s.
Nidaa Tounes won 86 seats in the October parliamentary polls, beating moderate Islamist movement Ennahda into second place with 69 seats.
Parliament picked deputy speakers Thursday from Ennahda and the third-placed Free Patriotic Union.
Under the North African country's electoral system, the party with the most votes has a mandate to form a coalition government.
Nidaa Tounes has said it will not form a government before the presidential runoff, in which Essebsi faces incumbent Moncef Marzouki after neither candidate secured an absolute majority in a November 23 first round.