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All In Baseball

You must be ALL IN if you want to succeed in life!

All In Baseball (AIB) was founded in 2022 with the goal of creating a better baseball community in the greater Atherton area. AIB is a 501(c)3 non-profit which is geared to enable today's youth to go All In on their lives.  Through community out reach, on field camps & clinics, mental performance classes and baseball essential skills,  All In Baseball will help you be better prepared for success in life. 

Every year, AIB offers camp & clinic scholarships to youth from underprivileged backgrounds in the East Palo Alto, East Menlo Park and Redwood City areas.

All In Baseball is proud to partner with The Miracle League of Redwood City to create a better sense of baseball community in the Bay Area. Members of AIB will help The Miracle League remain a world class organization!

All In Baseball is a non-profit organization created to give today's youth an opportunity to go "ALL IN" on their life. The staff at All In Baseball are 100% focused on Growth, Accountability, a Team First mentality, and Resiliency. 

Each and every day the All In staff is committed to helping you grow and achieve all of your goals. By living one pitch at a time, we can help you go ALL IN on your life aspirations on and off the field!



There are winners and learners. We will get 1% better every day!


There are 2 ways to do things "The Right way, and Again!"

One Pitch At A Time

We will use mental performance to focus on things we CAN control!

Sean McMillan


Phone: 650-430-1378

Sean McMillan became the Baseball Program Director at Sacred Heart Prep in Atherton, CA in August of 2021. Prior to that he was in his fifth season as Director of Operations for Santa Clara University.

McMillan, who was hired at SCU in December 2017. He came to Santa Clara from Junipero Serra High School in nearby San Mateo, California, where he served as an assistant coach for the varsity squad since May 2017, and the junior varsity head coach from 2015 to 2017.  

The 2015 University of Redlands graduate was a four-year starting catcher for the Bulldogs from 2011-15 and a three-time captain.  He finished his career with a .330 batting average and 141 RBIs in 156 career games.  McMillan was twice named first-team All-Southern California Intercollegiate Athletic Conference as well as to the All-West Region team.  

Coach McMillan brings a wealth of knowledge from all different levels of the game. Having experience at the Division I, Division III, high school and youth baseball, McMillan is a well rounded coach to relate to all playing levels. 

McMillan received his bachelor’s degree in creative writing and physical education from the University of Redlands in 2015 before obtaining his master’s degree in coaching and athletic administration from Concordia University in 2018.