The constituency represents the entire population of Miyagi Prefecture including the urban centre of Sendai. From the first House of Councillors election in 1947 until the 1992 election, Miyagi elected two Councillors to six-year terms, one at alternating elections held every three years. Under 1994 electoral reform Miyagi's representation was increased to four (two sets of two) from the 1995 election.
The district had 1,907,518 registered voters as of September 2015, the second-lowest of the 10 prefectures that were represented by four Councillors at that time.[2] By comparison, the Hokkaido, Hyogo at-large district and Fukuoka districts each had more than 4 million voters but were limited to the same number of Councillors as Miyagi.[2] To address this malapportionment in representation, a 2015 revision of the Public Officers Election Law decreased the representation of Miyagi, Niigata and Nagano districts to two Councillors while increasing Hyogo, Hokkaido and Fukuoka districts to six Councillors;[3] this change began to take effect at the 2016 election, at which time Miyagi elected only one Councillor, and was completed at the 2019 election when again, Miyagi only elected one Councillor. The district has been somewhat favorable to the opposition for the majority of its existence; it was briefly represented by two opposition members from 2019 to 2020, before Sakurai switched to the LDP. The CDP also defeated an incumbent LDP Councilor, Jiro Aichi, here in 2019.
The Councillors currently representing Miyagi are:
^Sakurai again changed parties after the DPP joined an opposition parliamentary group with several other parties including the CDP. This time he joined the ruling Liberal Democratic Party[7]
^"総務省|令和4年9月1日現在選挙人名簿及び在外選挙人名簿登録者数" [Ministry of Internal Affairs and Communications - Number of registered voters as of 1 September 2022] (in Japanese). Retrieved 2023-01-04.
^ ab"平成27年9月2日現在選挙人名簿及び在外選挙人名簿登録者数" [Number of resident and non-resident enrolled voters as of 2 September 2015] (in Japanese). 2 September 2015. Retrieved 11 March 2016.
^"櫻井 充(さくらい みつる):参議院" [Sakurai, Mitsuru: House of Councillors] (in Japanese). Retrieved 13 December 2016.
^"国民民主党、結党大会を開催" [Democratic Party for the People Holds Inauguration Convention]. qnew-news.net (in Japanese). Archived from the original on 2018-05-22. Retrieved 2023-01-19.
^"桜井参院議員が自民会派入り 国民民主は除名方針" [Sakurai Joins the Liberal Democratic Party - Expelled by the Democratic Party for the People]. Mainichi Shimbun (in Japanese). Archived from the original on 2020-06-03. Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第1回参議院議員選挙" [Miyagi At-Large District - 1st House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第2回参議院議員選挙" [Miyagi At-Large - 2nd House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第3回参議院議員選挙" [Miyagi At-Large District - 3rd House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第4回参議院議員選挙" [Miyagi At-Large District - 4th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第15回参議院議員選挙" [Miyagi At-Large District - 15th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第15回参議院議員補欠選挙" [Miyagi At-Large District - 15th House of Councillors By-Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第16回参議院議員選挙" [Miyagi At-Large District - 16th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"歴代参議院議員一覧" [List of Former Councillors] (PDF) (in Japanese). House of Councillors. 2014. Archived from the original(PDF) on 4 March 2016. Retrieved 11 March 2016.
^ ab"宮城選挙区 - 第17回参議院議員選挙" [Miyagi At-Large District - 17th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第17回参議院議員補欠選挙" [Miyagi At-Large District - 17th House of Councillors By-Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-20.
^ ab"宮城選挙区 - 第18回参議院議員選挙" [Miyagi At-Large District - 18th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第19回参議院議員選挙" [Miyagi At-Large District - 19th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第20回参議院議員選挙" [Miyagi At-Large District - 20th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第21回参議院議員選挙" [Miyagi At-Large District - 21st House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第22回参議院議員選挙" [Miyagi At-Large District - 22nd House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第23回参議院議員選挙" [Miyagi At-Large - 23rd House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第24回参議院議員選挙" [Miyagi At-Large District - 24th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第25回参議院議員選挙" [Miyagi At-Large District - 25th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.
^ ab"宮城選挙区 - 第26回参議院議員選挙" [Miyagi At-Large District - 26th House of Councillors Election]. go2senkyo.com (in Japanese). Retrieved 2023-01-19.