He was born on his father’s cotton plantation in eastern Georgia in 1798.  He was the second oldest of nine children.  Lamar was intensely curious and read voraciously as a child.  In his early adult years, he enthusiastically pursued a number of projects but had mixed success.  He spent time as a merchant and as a newspaper editor.  His well-connected family got him a job as personal secretary to the governor in 1823, which allowed him to travel the state and meet with many people.  In 1826, he married; and the couple soon had a daughter.

In 1828, he moved to the western Georgia community of Columbus and started a successful newspaper, the Columbus Enquirer, a paper that still operates as the Ledger-Enquirer.  Lamar was soon elected to the state senate.  After his wife died in 1830, he fell into a period of deep mourning and declined to seek re-election.  But he soon found a new purpose and began studying law.  He was admitted to the bar in 1833 and mounted a failing bid for Congress that year.

When his older brother died in 1834, a depressed Lamar traveled to Texas and stayed with his old friend James Fannin.  He soon returned to Georgia to settle his affairs before returning to Texas to stay.  By this point, the Texas Revolution had erupted.  Lamar volunteered for the Texas army immediately, initially serving as a private.  As the Mexican Army approached San Jacinto in April 1836, Lamar led a daring raid to rescue to fellow Texas soldiers surrounded by Mexican troops.   He was given command of a cavalry troop for the Battle of San Jacinto. 

Lamar was soon appointed the interim secretary of war for the newly independent Republic of Texas.  In the elections held in the fall of 1836, Lamar was elected vice-president, running on a separate ticket from the winner, Sam Houston.

Texas as an independent republic did not have political parties, but the clearest political lines were whether Texans supported or opposed Sam Houston.  Under the Texas Constitution of 1836, a president could not serve successive terms. 

The 1838 election quickly became a contest between Lamar, who often clashed with Houston, and a little-known senator, “Honest Bob” Wilson, who always claimed he would be just as honest as the circumstances permitted.  Lamar won in a landslide.

Lamar savored the victory and prepared an extensive agenda.  His ambitions were larger than the resources Texas had.  Unlike Houston, Lamar had an antagonistic attitude toward Native Americans and declared in his inaugural address that the tribes should either be “expelled or exterminated.”  He also called for a national bank, a school system, and a national university.  After Houston’s effort to secure annexation to the United States failed, Lamar announced he would oppose such efforts as president.

In 1839, he decided to move the capital from Houston, the namesake city of his chief rival, to the small settlement of Waterloo on the Colorado River.  The city was renamed Austin, and Lamar founded what became the Texas State Library as the official archives. 

Lamar laid the groundwork for public schools in Texas, but a statewide system would not be established until after the Civil War.  Thousands of acres of land were set aside as a trust for a university, but the University of Texas would not be established from this land until 1883.

Peace efforts with Mexico failed, and few governments were willing to recognize Texas.  In 1840, he defied Congress and sent an expedition to Santa Fe to try to consolidate the Texas claim on the Rio Grande as a border.  Lamar sent dozens of men with tens of thousands of dollars in goods to try to initiate trade with the distant city.  Upon their arrival, they were immediately arrested by Mexican troops in a diplomatic disaster for Texas. 

He sent the Texas Army to raid Native American settlements, but this resulted in a fierce response from the Comanches, who launched a fierce series of raids on settlements across Central Texas in 1841, leaving many casualties in their wake.

Government spending doubled, and inflation soared as the Texas dollar collapsed.  When he left office in 1841, succeeded by Houston, the national debt had quadrupled into millions of dollars.

After Texas was annexed and became a state in 1845, he was elected to the new state legislature representing Eagle Pass.  When war erupted with Mexico in 1846, the now 48-year-old Lamar was determined to serve.  He volunteered and was noted for his service at the Battle of Monterrey in September.  Afterward, he was assigned to command a small post in Laredo.

He continued to mange his plantation in Richmond after the Mexican War.  A book of his poems, Verse Memorials, was published in 1857.  Politics, however, was never far from his mind.  In 1857, President James Buchanan appointed Lamar to serve as US Ambassador to Nicaragua.  Shortly afterward, Buchanan named him to serve as ambassador to both Nicaragua and Costa Rica.

Lamar was proud of his work as ambassador.  His tenure became an impressive capstone to his career, but health problems increasingly made it difficult to serve.  He returned to his plantation in Richmond in October 1859 to recuperate but died of a heart attack two months later in December at age 61.

In later years, Lamar was widely praised for his efforts on behalf of education, though it took decades for those efforts to be realized.  In 1932, the new Lamar University in Beaumont was named for him.  Schools and streets across the state are also named for him.