Loyola College Cottle began his coaching career as a graduate assistant at Salisbury and then spent three years as the head coach at the
Severn School, where he compiled a 26–9 record. In 1983, he took over as head coach at
Loyola. In 1988, he led the Greyhounds to the
NCAA tournament, and repeated the feat each subsequent season of his career at Loyola for a total of 14 appearances. Each of those years, the Greyhounds finished the season ranked in the top ten. In 1989, Cottle guided his team to become the only one in school history to finish the regular season undefeated. In 1990, Loyola advanced through the
NCAA tournament to the final, before losing to
Syracuse. The Greyhounds finished the 1994 season with an 11–2 record, one of their best in history, and recorded
their first ever win over cross-town rival
Johns Hopkins, 17–15.
Maryland Cottle was hired as the head coach for the University of Maryland men's lacrosse team in September 2001. In his first season, 2002, the Terps finished 9–4 and did not qualify for the NCAA tournament. Beginning in 2003, Maryland made an appearance each subsequent season of Cottle's tenure. In 2003, the Terrapins appeared in the national tournament semifinals for the first time since 1998 and finished ranked number-three in the nation. The following season, Maryland won the
Atlantic Coast Conference (ACC) championship for the first time since 1998. In 2005, Cottle led the Terps to a second consecutive ACC title. Maryland again made Final Four appearances in 2006 and 2007. In 2008, Maryland had an attacking corps composed entirely of freshman, but advanced to the NCAA quarterfinals before being eliminated by
Virginia in an
overtime game. The Terrapins finished each of his nine seasons with a
winning percentage of no less than 0.625. The team also has advanced to the
NCAA tournament eight out of nine years. Cottle received criticism, however, due to his inability to lead his team to the NCAA finals. At the time, the Terrapins had not secured a national title since 1975, despite being the largest school in the state of Maryland, a traditional bastion of lacrosse talent. In 2001, some Maryland supporters had been critical of the athletic department's selection of Cottle over interim head coach Dave Slafkosky or former Syracuse star
Gary Gait, who was an assistant for the
Maryland women's team at the time.
Chesapeake Bayhawks In July 2010, the
Chesapeake Bayhawks of
Major League Lacrosse hired Cottle as a consultant.
Marquette University In December 2010,
Marquette University in the
Big East conference hired Cottle as a consultant. ==Personal life==