Leadership Team

Tanner Clinic is dedicated to providing comprehensive, accessible, high-quality family healthcare and specialty care on a personal level. Our motto is “Compassion, Courtesy, and Respect.” That mission goal begins at the top with the clinic’s administration and board of directors.

Marshall McKinnon, CEO

Marshall McKinnon has served as Tanner Clinic’s CEO since 1996. Under his leadership, Tanner Clinic has grown in reach and reputation, now offering more than 30 specialties in five locations, with more than 120 physicians and advanced practitioners.

Marshall earned a degree in International Finance from Brigham Young University before joining Tanner Clinic in 1990. He later completed an MBA degree. In 2011, he received the Utah Medical Practice Executive of the Year; he’s also a past president of the Utah Medical Group Management Association.

On a professional level, Marshall is known and respected for excellence in his communication and interaction with physicians and staff. He is skilled in health care management, physician and employee relations, strategic planning, managed care, health care regulation, customer service and physician recruitment.

Marshall is a native of Utah but grew up in Eugene, Oregon. He and his wife, residents of Kaysville, have six children. He enjoys BYU everything, reading, traveling, hiking, biking and family time.


Theron Stoker, COO

Theron Stoker, chief operational officer of Tanner Clinic, oversees the clinic’s financial and operational processes. Theron, who earned an MBA from Utah State University, joined Tanner Clinic in 1996. Prior to that, he served for 10 years as chief financial officer for a large clinic. He also managed an orthopedic practice in Salt Lake City for three years.

Theron has served as president of the Utah Medical Management Association, earning its highest honor, Medical Practice Executive of the Year in 2006.

Theron grew up in Logan, staying on for undergraduate and graduate work at Utah State University. There he earned a B.S. in accounting before completing his MBA.

He now lives in Layton, where he and his wife continue efforts in raising a family of seven children. They are also grandparents. Theron’s diverse interests include spending time with his family, “seeing things completed well,” and making a difference.


Kevin L. Mansfield, Human Resources and Marketing Director

Kevin L. Mansfield, director of human resources and marketing, is responsible for Tanner Clinic’s staff of 700 employees, including 120 providers.

Kevin came to Tanner Clinic in 2010 with a full roster of professional experience. He previously worked for IASIS Healthcare as human resources director for Davis Hospital and Medical Center and the Physician Group of Utah. Prior to that, he directed human resources at Convergys Corp. and CSFSdirect, Inc., which was purchased by E*Trade Financial.

He also handled human resource management duties at such large Utah corporations as RC Willey and Iomega Corp.

A graduate of Brigham Young University, Kevin has been active in many community and professional organizations including the Chamber of Commerce, United Way and Rotary. He is a member of the Society for Human Resources Management (SHRM), and has served as Utah president and national board member of the International Association of Business Communicators (IABC). Kevin lives with his wife in Kaysville, and they are the parents of two children.  He is an avid motorcycle rider and donut connoisseur.


Kevin SpainhowerKevin D. Spainhower, Business Services Director

As Tanner Clinic’s business services director, Kevin D. Spainhower CPA oversees the clinic’s business office. Much more than physician billing, insurance claims or financial reports, the business services director works to maintain good relationships with patients and physicians, as well as a staff of more than 110 people.

Kevin joined Tanner Clinic in 2007. He directs the departments that handle patient accounts and insurance billing. He also supervises reception, which takes phone appointments and welcomes patients to Tanner Clinic’s three locations.

Kevin came to Tanner Clinic with many years of experience in corporate finance. Most recently, he served as accounting manager at Optum Bank, the nation’s largest administrator of health savings account. His other positions include retail accounting manager for Associated Food Stores and controller for United Savings/Western Mortgage, later purchased by Washington Mutual.

Kevin earned a bachelor’s degree in accounting from Weber State University, following it up in two years by certifying as a CPA. He lives with his wife in Kaysville. They are the parents of four children. When he’s not watching the stock market or researching investments, Kevin likes yard work, golf and spending time with his family.


Nancy Fahrenbach, Clinical Services Director

Nancy L. Fahrenbach brings a solid history of teaching to her position as Tanner Clinic’s director of clinical services. She is the manager and coach for 200 medical assistants, RNs and LPNs who work with Tanner Clinic’s 120 providers.

Nancy came to Tanner Clinic in 2010 after multiple positions within Davis School District, including career and technical education curriculum supervisor and work-based learning coordinator. Prior to that, Nancy opened the medical assisting program at Ogden/Weber Applied Technology College. She moved on to the Davis Applied Technology College, opening its medical assisting program, the first school in the ATC system to become accredited.

She is also a seasoned, hands-on veteran of medical assisting, performing in family practice and specialty heart and cardiovascular clinics.

Nancy began her education in her native Rhinelander, Wisconsin, later earning a bachelor’s degree in health education. She obtained a Utah State teaching certificate with endorsements in health science and work-based learning.

Her position at Tanner Clinic closes a circle that began in the ATC. She placed and taught many of the clinic’s medical assistants; when she arrived, a quarter of the clinic’s MAs had been her students.

Nancy and her husband Bryan, who teaches anatomy and physiology at Davis High School, are the parents of two children. Outside of the clinic, you’ll find Nancy and her husband motorcycling through Utah’s mountains and backcountry. She also enjoys golfing and playing with her two Labs.


LaMar, Travis 1.JPG - EditedTravis LaMar, Ancillary Services Director

Travis LaMar has been with Tanner Clinic for nine years, serving as the imaging director for the past three years, overseeing x-ray, ultrasound, mammography, CT & MRI departments.

Travis came to Tanner Clinic in 2007 after previously working for Ogden Regional Medical Center where he completed his clinical education. He earned his bachelor’s degree at Weber State University, then went on to earn his Master of Health Administration degree from Weber State University as well.

He lives with his wife of 13 years in Davis County. They are the parents of three children, ages 9, 7, and 4. Travis enjoys spending time with his family and any activity that takes him outdoors, but especially snow skiing, water skiing and hiking the beautiful Wasatch mountains.


OLYMPUS DIGITAL CAMERANathan Dalling, Population Health Director

As population health director, Nathan Dalling maximizes potential revenue from incentive programs offered by insurance companies. He does this by understanding and managing the complexities of these programs.

Nathan is a graduate of BYU Idaho in healthcare administration, and then went on to earn a double masters in business administration and healthcare administration.

He interned here at Tanner Clinic as an administration intern before accepting a full-time position. Nathan took a short hiatus to experience cattle ranching with his family’s business, but recently rejoined Tanner Clinic with his current position.

Nathan and his wife have made their home in Farr West with their three children ages 4, 3, and 1. He enjoys playing basketball, riding horses along Utah’s gorgeous mountain trails, and enjoying the outdoors with his family camping and hiking.


OLYMPUS DIGITAL CAMERABrandon Cassel, Administrator

Brandon oversees the imaging, laboratory, satellite services, reception and appointment departments as well as urgent care and the overall patient experience at Tanner Clinic. Brandon joined Tanner Clinic in 2014. Prior to that, he managed a family practice clinic in Layton and worked at Lakeview Hospital. Brandon is also heavily involved in the local Medical Group Management Association and has served on their conference committee. Brandon completed a bachelor’s degree in microbiology and has received master’s degrees in health and business administration from Weber State.

Brandon’s passion, at work and in his personal life, is his commitment and dedication to improving the lives of those around him. He feels his role as a leader is to ensure those he leads are successful and views it as a personal failure if any one of his staff aren’t successful to their fullest extent. He believes the most important thing in life is to make sure others know he cares for them.

Brandon’s personal life includes dressing up regularly as a prince and having family room dance parties with his amazing wife, and their three beautiful girls.  They also have a baby boy who already enjoys watching football with his dad. Brandon enjoys spending time with his hound dog, playing sports specifically basketball and football, and closely following his beloved Washington Redskins.  Brandon is also very involved in Weber State University’s health administration program as an adjunct professor and a member of multiple committees.



Mike Millerberg brings extensive experience to his position as health information services director. His role oversees medical records, IT, and the NextGen system, which requires development and database support.

Mike graduated from Brigham Young University with a bachelor’s degree in computer science.  Before coming to Tanner Clinic seven years ago, he was a software developer manager with InterContinental Hotels, writing their reservation center software for 15 years. Mike parted ways with the company when they moved the development to Atlanta. Rather than move, Mike chose to stay in Davis County where he was raised, met and married his wife, and they raised their children.

He and his wife of 28 years have five children, four of whom followed in their dad’s footsteps and are attending or have graduated from BYU. His youngest is currently attending LDS Business College. With an empty nest Mike is learning new hobbies which he is putting to good use finishing his basement. He also enjoys spending time with family, camping, yard work, racquetball, and family history.


OLYMPUS DIGITAL CAMERAKathy J. Bennett, Clinical Services Director for Satellite Clinics

As clinical services director for satellite clinics, Kathy acts as a liaison between the satellite clinics and the main clinic, representing the satellites’ needs and offering support to the site supervisors.

Kathy has been with Tanner Clinic for 20 years. She began her career as an accountant and auditor with Hilton Corporation, and Wells Fargo, but Kathy knew she wanted to work in the medical field. With her family’s support, she went back to school earning her EMT certification, CNA certification, and her associate degree in Medical Assistant. She currently holds a certification from the AAMA for Medical Assisting.

Kathy lives in Davis County with her husband, Bryan. They have three children and four grandchildren. Her motto is “work to live not live to work,” and her many hobbies and interests certainly reflect that. Kathy and her husband enjoy spending their time outdoors rock crawling in their RZR, road or mountain biking, snowmobiling, or exploring back roads on her Harley. Never one to sit still, Kathy is also a 14-year volunteer with the Weber County Search and Rescue team, where she assists with medical training, managing the command center, and is part of two-person dog handling team with her husband. Kathy has an agility dog, Gingersnap, who is an AKC Open Agility Champion.