He represents Senate District 33, which includes parts of Saline County and southwestern Pulaski County.

During his first term as a senator in 2019, he sponsored numerous bills affecting health care in almost all of its many facets. He co-sponsored legislation that updated regulations governing the practice of nursing, the training of chiropractors, the licensure of physical therapists, the prescribing of painkillers and controlled substances, emergency medical treatment, assisted living palliative care, hospice care, the treatment of people with developmental disabilities and Medicaid reimbursements.

He was the Senate sponsor of Act 878 to provide for insurance coverage for treatment of pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, also known as PANDAS, and pediatric acute-onset neuropsychiatric syndrome, referred to as PANS.

In addition to health care, Senator Hammer's legislative priorities include the process for registering motor vehicles and renewing drivers' licenses. His list of bills also includes measures on municipal aid and workforce services.

Senator Hammer is a member of the Senate Committee on Public Health, Welfare and Labor and the Senate Committee on Transportation, Technology and Legislative Affairs. He also serves on the Joint Committee on Public Retirement and Social Security Programs and the Legislative Council.

He is a chaplain and pastor at Saline Memorial Hospice. He and his wife, Karen, have two sons and a daughter. He is a member of Saline Missionary Baptist Church in Tull.