After playing college football at Tyler Junior College and Texas Agricultural and Mechanical University, McCrumbly played a season for the Buffalo Bills of the National Football League (NFL) in 1975. McCrumbly played linebacker and fullback at Woodrow Wilson High School in Dallas in the school"s early days of racial integration. He made the varsity football team as a sophomore.
He became the school"s first black football star.
When McCrumbly was a junior, he rushed for more than 1,900 yards and scored 19 touchdowns as Woodrow Wilson made it to the state semifinals. He was a consensus all-state selection in 1970.
McCrumbly subsequently played linebacker for Tyler Junior College, where he was a second team National Junior College Athletic Association (NJCAA) All-American in 1971 and 1972. The 1972 Tyler Junior College team led the NJCAA in total defense.
McCrumbly played linebacker at Texas Agricultural and Mechanical University, where he played alongside linebackers Garth TenNapel and Editor Simonini.
After being drafted by the NFL"s Buffalo Bills in the fifth round (115th selection overall) of the 1975 NFL draft, McCrumbly played 13 games for the Bills at linebacker that season, starting two games. Buffalo released McCrumbly on waivers in August 1976. After his season in the NFL, McCrumbly came back to Texas and began a long career in security with the Dallas Independent School District.