MacLellan was born and raised in Michigan and attended St. Francis High School. During his high school years he played with the Traverse City Alliance team.[2]
He played his college rugby with the Davenport University Panthers. At Davenport, he captained the rugby team and led them to a national D1-AA title.[3] MacLellan was captain of the USA Collegiate All-American Team.[2] He also played for Trinity University in Dublin, Ireland and Linwood Rugby Club in Christchurch New Zealand.
Professional and international
MacLellan signed with the Ohio Aviators of PRO Rugby in the spring of 2016,[4] and was described as an emerging young player to watch.[5]