[6] He completed his primary and secondary education in Beypazarı and started attending Istanbul University in 1979, graduating with a degree in law in 1983.

Yavaş continued his legal practice and council membership until 18 April 1999, when he ran again and was elected mayor with 51% of the vote.

[6] Yavaş was the Republican People's Party's candidate for mayor in Ankara for the Turkish local elections held on 30 March 2014.

[8] At 20:30 local time on the day of the election, after voting had ended and the count was underway, he held a press conference declaring victory and urging his supporters to remain at voting stations to monitor the count despite very unfavorable preliminary result information from the Anadolu News Agency.

Yavaş stated that his campaign had filed objections with the local election authorities regarding numerous irregularities and urged his supporters, who had gathered in front of the Supreme Electoral Council, to stay calm.

In the election on 31 March, Yavaş became the first CHP Mayor of Ankara after 25 years of AKP (and its predecessor Virtue Party) rule, taking 50.9% of the vote compared to his rival's 47.1%.

Yavaş started his mayoral term by placing a freeze on the hiring of municipal personnel while investigations over corruption under the previous Justice and Development Party (AKP) continue.

[14] He was also praised for ordering the statue of Mustafa Kemal Atatürk in Ankara's Ulus district to be thoroughly cleaned, having been subject to years of negligence under previous mayors.

Yavaş stated that the attempted power-grab was unlawful and went against the council's bylaws, using his executive power to reject the proposed changes.

Polls conducted within the country in late 2020 showed that Yavaş would win if he faced Erdoğan in a potential presidential election.

Yavaş believed Ankara was debt-ridden because of incompetent politicians who were put into power for their affiliations to the AKP rather than merit.

[20] In terms of transportation and infrastructure, Yavaş has criticised the AKP for "neglecting" the issue for "many years," and has since contacted various firms to construct and preserve bicycle routes and pedestrian pavements to encourage Ankara citizens to decrease fossil fuel emissions.