Daniel Costanza joined the Saint Mary's baseball coaching staff in 2024 after serving as the lead assistant for Eric Valenzuela at Long Beach State. Costanza was then promoted to Associate Head Coach ahead of the 2025 season. At Long Beach State, Costanza worked with the infielders, assisting with the offense, and served as the primary recruiting coordinator.
Under his leadership, the Dirtbags ranked 36th in the nation with a .977 fielding percentage in 2021 and then finished 37th in the nation in 2022 at a .975 mark. The .977 in 2021 is the best for the program since 2017.
Costanza became a full-time assistant coach with the Gaels in 2016, previously serving as the team's director of baseball operations.
Costanza came to Saint Mary's for the 2013-14 season after spending two years as an assistant coach at Cal State East Bay. While with the Pioneers, Costanza worked both with hitters and infielders, coached first base and helped run the team's strength and conditioning program. In 2013, the Pioneers went a school-best 32-18 and had three infielders earn all-conference honors.
Prior to his stint at Cal State East Bay, Costanza served for two seasons as a hitting and infield coach at York College in Nebraska where he worked with junior varsity hitters and infielders. Costanza has also served as an assistant coach at Clayton Valley High School and helped to run camps at Clayton Valley as well.
Before becoming a coach, Costanza played for two years at York College under 2009-2010 MCAC coach of the year Nick Harlan. He was the starting second baseman on back-to-back MCAC Championship Teams in 2009-10 and 2010-11, and also won a MCAC Tournament Championship in the 2009-2010 season. York College earned a trip to the National Regional Tournament in Lubbock, Texas in the 2009-10 season, and the team was ranked as high as 23rd in the nation. York went on to win a second conference championship the following year and was ranked as high as 17th in the nation, but missed the National Regional Tournament by one spot.
Costanza played a total of 102 games and finished with a career batting average of .312 with 19 doubles, 4 home runs, 50 RBI, and 48 runs. On the defensive side of the ball, Danny fielded .950 his junior year with 7 errors and 18 double plays, and then .973 his senior year with only 5 errors and 26 double plays.
Costanza played his high school ball at De La Salle High School in Concord, Calif. He won back-to-back BVAL Championships at De La Salle his junior and senior years, as well as a North Coast Section Championship his junior year.
Costanza was born in Walnut Creek and was raised in Pittsburg by his parents Dennis and Jane Costanza. He has three siblings: a brother, Nick, who played Soccer at Cal Poly Pomona, a brother, Christopher, who plays baseball at York College, a his sister, Alicia, who plays soccer at Carondelet High School. Danny was a double major at York College and graduated Magna Cum Laude with a B.A. in General Studies and B.S. degree in Biology. Costanza attained his M.B.A. at Cal State East Bay in 2014.
