Smerlas, of Greek-American descent, graduated from Waltham High School in 1975, where he was a star football player and wrestler. He became a defensive lineman for Boston College before embarking on an NFL career. His 1990 autobiography, By a Nose, recounts his eleven years with the Buffalo Bills and their climb from cellar-dwellers to Super Bowl contenders.
Smerlas currently resides in Sudbury, Massachusetts and is a part-time co-host during football season on Sportsradio WEEI as well as a contributor to western New York radio stations WGR in Buffalo and WHAM in Rochester. Smerlas is an avid motorcyclist, who often rides to support various Boston based charitable organizations.
Smerlas's company, All-Pro Productions, Inc. is the leading telemarketer contractor and fundraiser for police, firefighter, and similar organizations and agencies in Massachusetts. All-Pro Productions, inc was one of the for-profit solicitor organizations profiled in a Worcester Telegram  article. The article was critical of several organizations which raise money in donations and return only a small percentage to the charity. According to state records obtained by the telegram All-Pro productions raised $559,042 since 2007 from donors for a Worcester firefighters memorial to honor the six who died in the 1999 Worcester cold storage fire. $379,041 (68%) of the money raised went to All-Pro productions and $180,001 has gone to the memorial. In 2010 All-Pro Productions raised $416,626 from donors for the Veterans outreach center metrowest which received $74,494(18%)