Some of the distinguished legal organizations he is a member of include:
* American Board of Trial Advocates (ABOTA) since 1983.
* President of San Francisco Chapter of ABOTA, 1998;
* President of CAL-ABOTA (all eight California Chapters), 2001.
* Fellow, American College of Trial Lawyers.
* Fellow, International Society of Barristers.
* Fellow, American College of Labor and Employment Law.
* President, San Francisco Trial Lawyers Association, 1990.
Mr. McGuinn has lectured extensively on employment litigation and written articles on employment litigation and age discrimination in employment.
He has tried to verdict more that fifty jury trials, including: Rulon-Miller v. I.B.M. (1984) 162 Cal.App.3d 241 (San Francisco Superior Court; gender discrimination; breach of the covenant of good faith); Ewing v. Gill (1992) 3 Cal.App.4th 601 (Santa Clara Superior Court; age discrimination); Kendall v. Thelen, Marrin, Johnson & Bridges, (San Francisco Superior Court Case No. 938116; age discrimination); Mancinelli v. I.B.M., (U.S. District Court, Eastern District of California, Case No. CIV-910-780); Norden v. Sequoia Ins., (Santa Clara County Superior Court Case No. 711409; age discrimination); Pooshs v. Fluoroware, Inc., (U.S. District Court, Northern District of California Case No. 93-1137 MHP; age discrimination); Davis v. KGO-TV (1998) 17 Cal.4th 436 (age discrimination); Kondilas v. Asia Source, Inc. (2001) (Alameda County Superior Court Case No. 768355-4; reverse race discrimination); Stephan v. Cellular Warehouse (2002) (Alameda County Superior Court Case Nos. C 829820-7, 833009-3 [Consolidated]; national origin discrimination); James Robinson v. Wave Division Holdings (2008) (San Mateo County Superior Court Case No. CIV 467905; disability and age discrimination); and Curran v. Schools of the Sacred Heart (2015), San Francisco Superior Court (age discrimination and violations of the Calif. Labor Code).
Mr. McGuinn has served as Judge Pro-Tem for the San Francisco Superior Court presiding over both jury and non-jury trials. He also serves as a private mediator.