John Callaghan has a broad practice, including civil litigation, commercial litigation, administrative issues, and regulatory offence work. He appears before all levels of courts and tribunals, including arbitration panels. His expertise is often sought for complex cases and he has been described as "unflappable" in his handling of the myriad cases in which he is involved. John served for two terms as an elected bencher of the Law Society of Ontario, which governs the legal profession in Ontario. John is a member of the Civil Rules Committee, having been appointed by the Chief Justice of the Ontario Superior Court of Justice. The Committee creates the rules governing court practice. John is co-author of Class Actions Law and Practice (LexisNexis Canada), the leading class action text in Canada. He has been recognized as a leading counsel by The Canadian Legal Lexpert® Directory, The Best Lawyers in Canada, Benchmark Canada, Chambers Canada, and Chambers Global in areas such as class actions, commercial litigation, and competition.