Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dr. John Nicholas Harker, DO

Individual provider Orthopaedic Surgery Physician · NPI 1013026269

Dr. John Nicholas Harker, DO is an Orthopedic Surgery in Largo, Florida. Graduated from Nova Southeastern College of Osteo Medicine in 1989, 37 years ago. Practices with Paul J Wisniewski DO Inc, a 19-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in California and Florida.

Years since qualifying
37
Trained at
Nova Southeastern College of Osteo Medicine
Licensed in
CA, FL
In the registry since
2006
Specialties on file
2
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

12955 Seminole Blvd
Largo, FL 33778-2399
Phone: (727) 586-4752
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 18523 Corwin Rd Ste A, Apple Valley, CA 92307-2300 — (909) 712-2764

Specialties & licences

Orthopaedic Surgery Physician (primary) Taxonomy 207X00000X · Licence OS-0006819 (FL)
Orthopaedic Surgery Physician Taxonomy 207X00000X · Licence 20A23999 (CA)

Record details

NPI number1013026269
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorYes
NPI enumeratedAugust 30, 2006
Last updated in NPPESSeptember 12, 2025
Certification dateSeptember 12, 2025
Mailing address12955 Seminole Blvd, Largo, FL 33778-2399

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyORTHOPEDIC SURGERY
Medical schoolNOVA SOUTHEASTERN COLLEGE OF OSTEO MEDICINE
Graduated 1989 (37 years in practice)
Group practice Paul J Wisniewski Do Inc — 19 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

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