Mumtaz Qadri had confessed to murder on the grounds that he objected to Mr Taseer's calls to amend the country's controversial blasphemy law.
Critics of the law say it can be used to persecute minority faiths and is sometimes exploited for grudges.
The assassination divided Pakistan, with many hailing Qadri as a hero.
Qadri was part of Mr Taseer's protection team but opened fire on the governor as he was about to get into his car in the capital, Islamabad, on 4 January.