In 2004, when incumbent State RepresentativeNan Rich could not seek another term due to term limits, Kiar ran to succeed her in the 97th District, which included Coconut Creek, Davie, and Weston in western Broward County. He faced Weston City Commissioner Barbara Herrera-Hill in the Democratic primary, and campaigned on providing seniors with assistance for purchasing prescription drugs and reforming the Florida Comprehensive Assessment Test. He was endorsed by the Sun-Sentinel over Herrera-Hill, which praised his "history of public service" and "energy and enthusiasm." Ultimately, however, Herrera-Hill defeated Kiar, winning 53% of the vote to his 47%. Herrera-Hill ended up losing to Republican nominee Susan Goldstein, so when Goldstein ran for re-election in 2006, Kiar ran against her. He faced executive recruiter Walter Birch in the Democratic primary, and campaigned on increasing access to health insurance for low-income individuals, improving public education, providing working families with affordable housing, and shutting down the Citizens Property Insurance Corporation, which Kiar called a "mess" plagued with corruption. Kiar comfortably won the primary with 64% of the vote, and advanced to the general election. He was supported by Michael Schiavo, the wife of Terri Schiavo, who was kept on life support while her husband wished to allow her to die when a number of state politicians got involved. He criticized Susan Goldstein for supporting intervention in the case, declaring, "Susan Goldstein decided she knew what was best for me and my family. should apologize not just to me but the people who voted for her." During the campaign, Kiar was criticized for accepting campaign contributions from Chris Kovanes, a former Davie Town Administrator who was accused of embezzling hundreds of thousands of dollars, which Kiar called "despicable." Kiar advocated for the creation of a publicly elected state insurance commissioner to reform home insurance, the enaction of property tax breaks for "first-time homebuyers and public servants such as teachers, firefighters, and police officers," and the preservation of the state's Class Size Amendment. In the end, Kiar narrowly defeated Goldstein, unseating her with 53% of the vote. When he ran for re-election in 2008, he was opposed by Todd Goberville, a salesman and the former Chairman of the Florida Federation of Young Republicans. Goberville attacked Kiar for ineffectiveness in the legislature while Kiar criticized Goberville for opposing stem cell research and supporting school vouchers. He received the endorsement of the Sun-Sentinel in his campaign, which praised him for being "sincere, if not overly idealistic" and argued that "he deserves the chance to be a fence mender" in the legislature. Ultimately, Kiar ended up defeating Goberville handily, winning re-election with 58% of the vote. In 2010, he was re-elected to his third and final term in the legislature without opposition.
In 2012, rather than seek re-election to the legislature, Kiar instead opted to run for the Broward County Commission from the 1st District, which includes Davie, Lauderhill, Plantation, Sunrise, Tamarac, and Weston in western Broward County. Though he was initially opposed by a number of candidates, all of them dropped out, and he won election to the County Commission entirely unopposed.
Broward County Property Appraiser
Marty took office as the Broward County Property Appraiser on January 3, 2017 having been elected unopposed in 2016.