Andrew P. McCormick, jurist and state senator, was born on December 18, 1832, at McCormick's Ferry on the San Bernard River in Brazoria County, the son of Joseph M. and Agnes Louisa (McKenzie) McCormick. After preparatory education in a series of private schools, where he was taught by Thomas J. Pilgrim, John McCullough, and John Sayles, McCormick entered Centre College in Danville, Kentucky, in 1850. He graduated as valedictorian of his class in 1854. After returning to Texas he read law with his cousin, James Hall Bell, was admitted to the bar in December 1855, and became Bell's law partner. He married Mary Jane Cope of Brazoria County on September 8, 1859. At the outbreak of the Civil War, McCormick was a wealthy man, with seven slaves and property worth more than $20,000. He entered the Confederate Army and served in a regiment commanded by Col. Joseph Bates. McCormick, however, was not an enthusiastic secessionist and, like Bell, worked with Unionists after the war and became a Republican. Provisional governor Andrew J. Hamilton appointed him chief justice of Brazoria County in 1865. He served one year in that office, was elected to the Constitutional Convention of 1866, and supported the candidacy of Elisha M. Pease for the governorship that year. During congressional Reconstruction, McCormick was elected to the Constitutional Convention of 1868–69 and supported the moderate Republican candidate, Hamilton, against Edmund J. Davis in 1869. He received consideration as a running mate for the office of lieutenant governor with Hamilton but was ineligible because Congress had not removed the political disabilities placed on him for serving in the Confederate Army. Mary (Cope) McCormick died in January 1870, leaving six children. McCormick married Lula Bell on March 15, 1871, and his family eventually increased to ten children.
In September 1871 Governor Davis appointed McCormick judge of the Eighteenth Judicial District, which included Brazoria County. He held that position until April 1876, when, following adoption of the Constitution of 1876 and his election to the state Senate, he resigned. He represented Galveston, Brazoria, and Matagorda counties in the Senate of the Fifteenth and Sixteenth legislatures (1876–79). He was one of only a handful of Republicans to serve in the post-Reconstruction state Senate. In January 1879 President Rutherford B. Hayes appointed McCormick United States attorney for the Eastern District of Texas. However, before he qualified for that position, Congress established the Northern Judicial District in Texas, and in April 1879 Hayes made him judge of that new federal court. He served as judge of the Northern Judicial District until 1892, living for most of that time in Dallas. On March 17, 1892, President Benjamin Harrison appointed McCormick to the United States Circuit Court of Appeals for the Fifth District, a position that he held for the rest of his life. He suffered a serious injury in a fall in 1911 and spent his last five years in a wheelchair. He moved from Dallas to Waco, the home of Andrew P. McCormick, Jr., in 1913 and died there on November 2, 1916. McCormick was a life-long Presbyterian and a Mason; he was buried in Greenwood Cemetery, Dallas, and was survived by his wife and ten children.