O’Brien was an exceptional player in football, basketball and baseball at Anniston High School in the late 1930’s. While at Anniston O’Brien was first team All-State as a halfback in his sophomore (1936), junior (1937) and senior (1938) seasons. O’Brien’s accomplishment was even more extraordinary then than it would be today because, at the time O’Brien was chosen, only one All-State team was named and selections were dominated by players from Birmingham.

In his senior season, O’Brien suffered a severe injury to his left knee against Oxford in Anniston’s third game of the season. The following week he was held out against Tallahassee until the fourth quarter. With Anniston trailing 7-2, O’Brien entered the game and personally covered the last 27 yards of the winning drive in three plays, scoring on a 12-yard run. The play preserved an undefeated season for the Bulldogs but O’Brien injured his knee again. He completely missed three of the next four games, playing only the first half against the fourth, then returned for Anniston’s season ending game against Gadsden. That game closed in a 6-6 tie as O’Brien scored Anniston’s lone touchdown on a 35-yard run.

No more than 5-feet-11 inches tall, O’Brien was named first team all-tournament as a center at the 1939 Alabama High School Athletic Association state basketball tournament. His Anniston team finished fourth in the tournament. Professionally, baseball was O’Brien’s sport. After a short stay with the University of Tennessee freshman football team, O’Brien left football for baseball. He signed his first professional contract with the Atlanta Crackers in July 1940 and played at Spartanburg, South Carolina, and in Anniston, Alabama, that season and Savannah, Georgia, in 1941, earning a promotion to Atlanta. With Atlanta in 1942 he threw out four Knoxville runners in one game, setting a Southern League record at the time.

In 1943, O’Brien moved to the Pittsburgh Pirates. That year he had seven consecutive hits in a double header against the New York Giants and batted .310 in 89 games. It was the first of the five years he spent in the major leagues. His best major league season came with Pittsburgh in 1945 when he batted .335 in 58 games.

Following the 1945 season, O’Brien played minor league baseball with several clubs including the Birmingham Barons in 1948. The center fielder helped the Barons to the 1948 Dixie Series championship over Fort Worth, hitting .359 with 19 homers, eight triples, 51 doubles, 131 runs scored and 137 RBIs.

In 1949, he returned to the majors with the Boston Red Sox. Following a trade to the Washington Senators in May 1950 he went to Louisville, Kentucky, Washington’s top minor league team. O’Brien played six more minor league seasons closing his career in 1955 as player-manager for Orlando of the Florida State League. In his final season, O’Brien played in 55 games. In 102 at-bats, he hit .373 with five home runs and 41 RBIs.

Following his retirement from baseball, O’Brien returned to Anniston and served as an official for many years. He died November 5, 1978.