O'Brien in 2016 at Stephen Schott Stadium.
|Born||1971 (age 48–49)|
|1993–1995||UC San Diego|
|Position(s)||First baseman/third baseman|
|Coaching career (HC unless noted)|
|1996–1997||UC San Diego (asst.)|
|1998–2011||UC San Diego|
|Head coaching record|
|Tournaments||NCAA D-II: 11–9|
|Accomplishments and honors|
Daniel Peter O'Brien (born 1971) is an American baseball coach who currently works in the player development department of the San Francisco Giants organization. He was named to that position prior to the 2018 season.He previously coached Santa Clara University and the University of California, San Diego's baseball programs.
Education and minor league playing career
O'Brien played at UC San Diego, led the team in home runs, continues to rank highly on several career lists. In his first year, he helped the team to a third-place finish in the NCAA Division III Baseball Championship. He then served as a player/coach for one season with the independent league team Greenville Bluesmen in 1996.
In 1997, O'Brien became a full-time assistant at UC San Diego. After two years, he was elevated to the top job. After three seasons, the Tritons moved the program to Division II, joining the California Collegiate Athletic Association. O'Brien helped establish the Tritons as a strong program in the CCAA, leading them to the College World Series in consecutive years, finishing third and second in 2009 and 2010, respectively. He took over a struggling Santa Clara program in 2012, and has sought to rebuild it in his first two seasons.
On May 24, 2017, O'Brien resigned from Santa Clara.
Since resigning from field coaching, he has operated TEN90 Coaching Group, a company that specializes in baseball talent development. In 2018, San Francisco Giants then-Director of Player Development David Bell hired O'Brien to the development staff of the Giants. He has since held the title of Development Coach for the Giants. 
Head coaching record
|UC San Diego Tritons (NCAA Division III independent) (1998–2000)|
|1998||UC San Diego||20–18|
|1999||UC San Diego||19–18|
|2000||UC San Diego||22–13|
|UC San Diego (D-III):||61–49 (.555)|
|UC San Diego Tritons (California Collegiate Athletic Association) (2001–2011)|
|2001||UC San Diego||14–34||7–28||11th|
|2002||UC San Diego||30–23–1||23–17||5th|
|2003||UC San Diego||25–28||19–19||T–6th|
|2004||UC San Diego||35–24||22–18||5th|
|2005||UC San Diego||37–20||23–17||2nd (North)|
|2006||UC San Diego||35–24||23–13||2nd|
|2007||UC San Diego||37–25||24–12||4th||NCAA D-II Regionals|
|2008||UC San Diego||43–18||25–11||2nd||NCAA D-II Regionals|
|2009||UC San Diego||41–15||27–9||1st||NCAA D-II Fourth Place|
|2010||UC San Diego||54–8||35–5||1st||NCAA D-II Runner-Up|
|2011||UC San Diego||42–15||29–11||1st||NCAA D-II Regionals|
|UC San Diego (D-II):||393–234–1 (.627)||257–160 (.616)|
|UC San Diego (total):||454–283–1 (.616)||257–160 (.616)|
|Santa Clara Broncos (West Coast Conference) (2012–2017)|
|Santa Clara:||128–194 (.398)||53–103 (.340)|
Postseason invitational champion
- "Dan O'Brien". Santa Clara Broncos. Retrieved January 11, 2014.
- "Bio - Dan O'Brien". UCSD Tritons. Retrieved January 11, 2014.
- Fitt, Aaron (July 1, 2011). "Coaching Roundup: Santa Clara Hires UCSD's Dan O'Brien". Baseball America. Retrieved January 11, 2014.
- "Dan O'Brien". baseball-reference. Retrieved May 26, 2017.
- Patronis, Amy Farnum (February 19, 2012). "O'Brien changes vibe at Santa Clara". NCAA. Retrieved January 11, 2014.
- "Head Baseball Coach Stepping Down". Santa Clara Broncos. May 24, 2017. Retrieved May 25, 2017.
- Career statistics and player information from Baseball-Reference (Minors)