Mike grew up in Fayetteville New York where he began playing the game of lacrosse as soon as he could walk, learning from his Grandfather, Tom Hall, who started the high school program at Fayetteville Manlius.
Mike finished his high school career in 2010 earning All-American Honors, making his way to Cornell University where he was a 4 year starting midfielder for the Big Red. Cornell went on to win 3 Ivy-League Championships and 1 final four appearance in 2013.
After college, Mike continued his career playing professional lacrosse for the MLL Ratters and Blaze and finished his career with the PLL Chrome in 2019.
While continuing to play at the professional level, Mike started coaching the game for 3d Lacrosse in Denver where he helped manage boys teams and programming until 2018 when he took over as Director of the 3d Colorado Girls Program. In only a few years, he was able to take the program to 11 club teams and 35 collegiate commitments (16 Division I).
Mike has also impacted the boys and womens high school world out in Colorado as he remains the Head Coach of Kent Denver Girls and has spent multiple years with Arapahoe, Mountain Vista and Boulder High.
Mike O'Neil continues to grow and teach the men's and women's game as a full-time JM3 coach and consultant.