He was also the twelfth and final Secretary of Treasury of the Republic of Texas during Anson Jones' presidency.

[5] Anson Jones, the last president of the Republic of Texas, appointed him as secretary of the treasury[4] in July 1845.

[4] The same year, while serving as Lieutenant Governor, he challenged Peter H. Bell for the governorship in 1851.

He was the president of an Austin convention to formally organize the Democratic party in Texas in January 1854.

He died on July 4, 1855, after falling ill while campaigning for the governorship against the incumbent, Elisha M. Pease, four months before the election.

[1][5] John A. Greer was originally buried at his farm, located nine miles northwest of San Augustine.