In 1874, Baker joined the Houston Light Guard, a local militia organized the previous year.
One of its members, Jonas Shearn Rice had attended TMI, and sought Baker as a member.
The Houston Light Guard was a vehicle for local social networking, as many lawyers and business leaders joined the militia or lent it material support.
William Marsh Rice owned fifteen mortgage bonds drawn for the unit, and two of his nephews were members, including another TMI graduate and future mayor of Houston, Horace Baldwin Rice.
Local newspaper publisher Allen Charles Gray campaigned for the group and gave it favorable coverage, while his brother Edwin Fairfax Gray, a Civil War veteran, trained and drilled the first wave of recruits.
The gray and black uniforms of the militia's early days revealed their allegiances to the Confederacy and the Lost Cause, though the militia replaced these uniforms in the 1880s with a scheme based on blue pants and red coats.

In May 1878, Baker was promoted to first sergeant.
He received a promotion to captain in August 1879, after which he led the honor guard presented to President Grant for his visit to Houston in 1880.
He resigned his commission and retired from active duty in the early-1880s.
For decades, he attended group functions and supported the Light Guard as an advisor, promoter, and fundraiser.
In 1874, Baker joined the Houston Light Guard, a local militia organized the previous year. One of its members, Jonas Shearn Rice had attended TMI, and sought Baker as a member. The Houston Light Guard was a vehicle for local social networking, as many lawyers and business leaders joined the militia or lent it material support. William Marsh Rice owned fifteen mortgage bonds drawn for the unit, and two of his nephews were members, including another TMI graduate and future mayor of Houston, Horace Baldwin Rice. Local newspaper publisher Allen Charles Gray campaigned for the group and gave it favorable coverage, while his brother Edwin Fairfax Gray, a Civil War veteran, trained and drilled the first wave of recruits. The gray and black uniforms of the militia's early days revealed their allegiances to the Confederacy and the Lost Cause, though the militia replaced these uniforms in the 1880s with a scheme based on blue pants and red coats.
In May 1878, Baker was promoted to first sergeant. He received a promotion to captain in August 1879, after which he led the honor guard presented to President Grant for his visit to Houston in 1880. He resigned his commission and retired from active duty in the early-1880s. For decades, he attended group functions and supported the Light Guard as an advisor, promoter, and fundraiser.
James A. Baker (born 1857)