In 1838, Guerra became an Administrator. In 1849, he served as a delegate representing Santa Barbara District at the First California Constitutional Convention.[1]
On 1 May 1851, he nearly resigned from the State Senate,[1] but returned to the position which he held until 1861 when he became the leader of the senate, which led to his term as acting lieutenant governor.[2]
From 1861-62, he served as the Acting Lieutenant Governor. From 1863-73 he was the District Judge for the 17th Judicial District.[1]