John S. McKiernan

{{Infobox Governor |name=John Sammon McKiernan |image= RI Governor John S. McKiernan.jpg |order=62nd |office=Governor of Rhode Island |term_start=December 19, 1950 |term_end=January 2, 1951 |lieutenant=Vacant |predecessor=John O. Pastore |successor=Dennis J. Roberts |birth_date=October 15, 1911 |birth_place=Providence, Rhode Island |death_date=March 9, 1997 (aged 85) |death_place=East Greenwich, Rhode Island , U.S. |party=Democrat |spouse=Elizabeth St. Pierre |profession=Lawyer |religion=Roman Catholic |order2= |office2= Lieutenant Governor of Rhode Island |term_start2= 1947 |term_end2= 1950
1951–1956 |governor2= John O. Pastore (1st time)
Dennis J. Roberts (2nd time) |predecessor2= John O. Pastore (1st time)
None – himself before vacant |successor2= Vacant
Armand H. Cote (2nd time)

| nickname        = 
| allegiance      =  United States
| branch          =  United States Army
| serviceyears    = 1943-1944
| rank            = 
| unit            = 
| commands        = 
| battles         = [[World War II, Italy]

}} John Sammon McKiernan (October 15, 1911 – March 9, 1997) was the United States Democratic politician, who served as the Lieutenant Governor of Rhode Island from 1947–1950 and 1951–1956 and briefly the 62nd Governor of Rhode Island (1950–1951).

Born in Providence, Rhode Island, McKiernan graduated from the University of Notre Dame in 1934 and from Boston University School of Law in 1937. After this, he went on to run his own law practice. and serve as legal advisor to the Providence Civil Service Commission as well as chairman of the Providence Fair Rents Committee in 1941.

In 1942 and 1943 he served as the first Assistant City Solicitor for Providence. After a break caused by his service in the US Army he retook this post.

He was elected the lieutenant governor in November 1946 and took office in January 1947. The governor at the time was John O. Pastore, a fellow Democrat. He was re-elected lieutenant governor in 1948.

As lieutenant governor and presiding officer of the state Senate in 1949, McKiernan cast the tie-breaking vote that resulted in the adoption of new rules effectively giving Democrats control of the Senate’s legislative committees for the first time in more than a decade. He was re-elected to a third term as lieutenant governor in November 1950.

After Governor Pastore left office early to become a United States Senator, following a special election to replace Senator J. Howard McGrath who was appointed United States Attorney General, McKiernan became governor and served for only 15 days from December 19, 1950 to January 2, 1951. His was the shortest term as governor in the history of Rhode Island. He resumed the office of lieutenant governor on January 2, 1951, under administration of another Democrat, Governor Dennis J. Roberts.

After winning re-election in 1952 and 1954, McKiernan resigned as lieutenant governor in 1956 to accept an appointment as an associate justice of the Rhode Island Superior Court.

A Roman Catholic, he was married to Elizabeth St. Pierre. He is survived by his four children, Mary E. McKiernan, John S. McKiernan III, William P. McKiernan and Laura E. McKiernan.