State Legislature

Post-Legislature

In June 1981, he was elected chairman of the Hawaii Republican Party with 341 out of 572 votes.^[34] During his tenure as chairman, he attempted to change the party's predominantly Caucasian image and to organize the party in every precinct.^[35] He refused to resign after the party's poor performance in the 1982 elections; on November 5, 1982, two party officers resigned in protest. Carroll eventually chose not to seek reelection in 1983.^[36]

In 1979, he had invested in a diamond mine; in 1994, he filed for bankruptcy, claiming that two business partners attempted to take over his company. In 1998, Carroll ran for Hawaii's 1st Senate District, but was defeated in the general election by Lorraine Inouye.

On May 25, 2000, he announced that he would run in the Senate election against Senator Daniel Akaka, and easily won the Republican nomination. In May, he had stated that he would need $1.5 million to launch a viable campaign against Akaka, but by late October Carroll had raised less than $2,000 - while Akaka had raised $430,000.^[37][38] He ran campaign ads that opened with, "Aloha, I'm John Carroll, and in no way am I a racist;" in the general election, he lost to Akaka.^[39]

On November 10, 2001, he announced that he would challenge Linda Lingle for the Republican nomination for governor in the 2002 election. He described Lingle as "unelectable," referencing her support in 1998 from anti-Cayetano voters who would remain Democratic in the 2002 election.^[40][41] However, he was defeated in a landslide in the primary, receiving less than 10% of the vote; Lingle received almost 90% and went on to win the general election. Carroll ran unsuccessfully for the United States House of Representatives in 2002. On May 27, 2009, he announced that he would challenge Lieutenant Governor Duke Aiona in the Republican gubernatorial primary, but received less than 5% of the vote.^[42]

On September 21, 2011, he announced that he would run for the Republican nomination for Senate against Linda Lingle; he campaigned against the Jones Act and a Native Hawaiian federal recognition bill.^[43] In the primary, he was again defeated by Lingle (she took over 90% of the vote); Carroll later endorsed Democratic Representative Mazie Hirono in the general election.^[44] In 2016, he announced that he would run in the Senate election and easily won the Republican nomination against other perennial candidates, but was defeated in a landslide by incumbent senator Brian Schatz.

In 2017, he faced potential disbarment over two 2015 complaints of professional misconduct and agreed to give up his law license.^[45]

Following the 2018 Hawaii false missile alert message sent by the State of Hawaii's Emergency Management Agency to hundreds of thousands of Hawaii residents via their phones on January 13, 2018, Carroll dubbed the incumbent Democratic governor David Ige "Doomsday David" and called on him to resign.^[46]

In 2018, he announced that he would seek the Republican nomination for governor. In mid-March, Carroll was leading state House Minority Leader Andria Tupola in the Honolulu Star-Advertiser's statewide poll of likely 2018 Republican voters by a margin of 12 percentage points, with 40% of potential Republican voters supporting Carroll as opposed to 28% supporting Tupola.^[47] Carroll was eventually defeated by Tupola by a 20% margin in the August 11 primary.

On June 14, 2019, Carroll announced his candidacy for the 2020 Honolulu mayoral election. He placed eighth in the primary, receiving 0.7% of the vote.^[48]

He died on September 19, 2021, in Oahu, Hawaii, at age 91.^[49]