Robert James Calder was born in 1810 to James H. and Jane E. (Caldwell) Calder in Baltimore, Maryland. His father died when he was a child, and Robert and his mother moved to Kentucky, where he was raised in part by his mother's family. They moved to Texas in 1832, arriving in Brazoria after the Battle of Velasco that June.
Calder immediately joined Texas forces and the cause for Texas Independence, and was among colonists who took up arms against Mexico in October 1835. He was with Gen. Stephen F. Austin's forces during the Battle of Concepción in San Antonio and accompanied Capt. James Walker Fannin on a recruiting mission. In 1836, he joined the army at Gonzales and became Captain of K Company, First Regiment of Texas
Volunteers, serving in that capacity at the Battle of San Jacinto on April 21 of that year. Following the Texans defeat of Gen. Santa Anna and his troops, Gen. Sam Houston dispatched Calder and three other men to take news of the victory to interim government officials on Galveston Island.
In 1836, Texas President David G. Burnet appointed Calder Marshal of Texas. Calder also received 640-acres for his military service in Brazoria, where he wed Mary Walker Douglass in 1837. Calder became mayor and later county sheriff, chief justice and probate-judge. When the couple and their children moved to Fort
Bend County, Calder became mayor of Richmond, serving also as justice and judge in that county. He later operated a mercantile and law practice.
In 1881, Calder unveiled a Galveston monument memorializing the nine Texans killed at the Battle of San Jacinto. Calder's many years of service as a public official
are indicative of his commitment to Texas, first as a republic and later as a state.