McDaniels was drafted by the Seattle SuperSonics in the second round of the 1971 NBA Draft and by the Utah Stars in the ABA Draft, but he began his professional career with the Carolina Cougars of the American Basketball Association, who offered him a $1.35 million contract to be paid over twenty-five years. Reportedly, the Cougars first approached McDaniels during November 1970, while he was still playing for Western Kentucky. McDaniels averaged 26.8 points and 14 rebounds in 58 games with the Cougars during the 1971-72 season and appeared in the 1972 ABA All-Star Game. However, he feuded with the Cougars while trying to renegotiate his contract – he wanted his salary to be spread over fifteen years, rather than twenty-five – and near the end of his rookie season he decided to leave the Cougars for the SuperSonics.
McDaniels remained with Seattle for the next two full seasons. However, he struggled to maintain the same level of production he had achieved in the ABA, and by the 1973-74 NBA season, McDaniels was averaging just 5.5 points per game. During that time, McDaniels was dogged by off-court troubles as the Cougars questioned the legality of his jump to the NBA. He later admitted in an interview, "I should have stayed in the ABA for a couple of years. I was just young and things started going bad for me there and I didn't know how to handle them." Sonics general manager Bill Russell ultimately released McDaniels in fall 1974. For the next four years, McDaniels bounced from team to team, playing for the Los Angeles Lakers and Buffalo Braves of the NBA, the Kentucky Colonels of the ABA, and Snaidero Udine of Italy. He finally decided to retire from basketball in 1978.
McDaniels currently resides in Bowling Green, Kentucky. He has two sons (Eskias McDaniels, Shannon Martin). His #44 jersey was retired by Western Kentucky in January 2000.