At the young age of 19, William “Bill” Mitchell started his work in golf by working as a greenkeeper. He spent his next few years working as a superintendent while managing a turf farm. Through these experiences, he gained firsthand knowledge of golf course construction, while creating connections in the industry, such as Orrin Smith, who he helped assist in several layouts throughout New England.

In the late 1940’s, Mitchell and his two brothers, Samuel and Henry, created a golf course architecture firm known as Mitchell Brothers. It lasted until 1954, and while the other brothers left the field of architecture, Mitchell stayed committed to the profession full-time. By the 1970’s, Bill Mitchell was responsible for over 150 original designs and 200 remodeling projects. He was an advocate for building golf courses specifically for women’s golf and was retained by the LPGA to create such a course. Mitchell passed away in 1974, but his designs and innovative thinking for the game has forever shaped the design footprint of golf.

William Mitchell is also credited with coining the term "executive-length course." Usually, courses with an 18-hole par between 55 and 66; derived from the expectation that executives would be able to enjoy a round of golf within the business day and still meet their commitments. In the 1960s, Mitchell reasoned that “...such courses could be quickly and enjoyably played by business executives at the tail end of a hectic workday.” A short par-55 executive layout may measure just 2,500 yards, while a par-62 executive might approach 5,000 yards; a wonderful aspect of executive courses is that they have the widest range of all course types in terms of length, filling the yardage gap between par-3 courses and regulation courses.

Mitchell was elected to ASGCA membership in 1969 and was involved with the organization until his death in 1974.