Born on January 2, 1913 in Baltimore, Church Yearley started his lacrosse career at the age of thirteen. This early interest was generated by the award of a lacrosse stick as a Sunday School prize by his teacher, Douglas C. Turnbull, Jr., a long-time member of the Hall of Fame. Church played two years with the Hopkins Midgets, an organized team of pre-high school boys, before entering City College. At City he earned letters in 1928, 1929 and 1930 and was elected captain of the team in 1930. That same year, he was named to the All-America Scholastic Team.
Matriculating at Johns Hopkins University the following fall, Church earned a minor letter his freshman year and was a regular in the seasons of 1932, 1933 and 1934. In 1932, he played on the U.S. Olympic Team. He was named to the All-America teams in 1933 and 1934 and was selected to play on the All-Star Team in both of those years.
After graduation, he moved to New York and continued his lacrosse with the Crescent Club of Brooklyn. In 1936 he switched his allegiance to the Mt. Washington Club and commuted to Baltimore each weekend for games. Church was elected to the executive board of the U.S. Intercollegiate Lacrosse Association in 1936 and served until a move to Atlanta, Georgia ended his active participation in lacrosse.
Following four years in the Navy during World War II, he returned to Baltimore with the Equitable Trust Co., staying with them until 1953 when he left Baltimore to become associated with the First National Bank of Atlanta. He became, successfully, assistant vice president, vice president, executive vice president, and vice chairman of the board. He also served as a trustee of Johns Hopkins University.