In the 1960s, Yablonski's father, Jock, made a number of attempts to reform the United Mine Workers of America (UMWA).
Jock Yablonski's five suits alleged that: Boyle and UMWA had denied him use of the union's mailing lists as provided for by law, he had been removed from his position as acting director of Labor's Non-Partisan League in retaliation for his candidacy, the UMW Journal was being used by Boyle as a campaign and propaganda mouthpiece, UMWA had no rules for fair elections and printed nearly 51,000 excess ballots which should be destroyed, and UMWA had violated its fiduciary duties by spending union funds on Boyle's re-election.
[1] Three weeks after the balloting ended, Jock Yablonski, his wife and their 25-year-old daughter Charlotte were murdered by three assassins hired by Boyle and paid for with embezzled union money.
For nearly 30 years, Yablonski has served as outside counsel for the National Football League Players Association (NFLPA), as well as other labor groups and union activists.
In 1992, he won a class action lawsuit in which a federal jury awarded $10 million in damages to former National Football League (NFL) reserve players.
He is a member of the Association of Trial Lawyers, and sits on the board of directors of the David A. Clarke School of Law Foundation.
Yablonski is also a former board member of the National Bank of Washington, which at one time was owned by the United Mine Workers.
Yablonski holds a press release, saying "The events in Washington, Pennsylvania show that murder is as institutionalized within the UMWA as it is in the mafia.