He practiced as a solo practitioner for a number of years, and during that time he established a reputation for quality medical care. In 1936, Dr. Steck recruited an associate, Dr. Mollerus Couperus, who remained with Dr. Steck until the war year of 1940. During that period, Dr. Steck purchased property at 1037 Market Street in Chehalis and remodeled the residence into medical offices. This was to remain the location of Dr. Steck's medical practice for almost forty years.

At various times and for varying periods of time, other physicians joined Dr. Steck as associates.

In 1960, the medical staff consisted of four doctors. During that year, Dr. Steck sold the medical practice, including the building and equipment, to a partnership including Dr. Maddox, Dr. Twiss, and Dr. Mouchon. A building addition and new physicians soon followed.

During the 1970s, the group realized that additional office space was needed. In 1975, after considerable planning and discussion, a modern, 13,000 sq. ft. medical building was built on ten acres of land on Bishop Road.

Dr. Steck passed away in 1971 and the medical group's name was changed to L.G. Steck Memorial Clinic to commemorate and perpetuate his memory.

In 1983, the Cowlitz Valley Medical Center was built in Winlock, Washington, as a satellite facility. It was sold in 1990. In 1991, The Centralia Specialty Center was built near Providence Hospital. SMG departments of Internal Medicine, Cardiology, and Family Practice are located there.