Židan, a veterinarian by education, was backed by 49 members of the 90-strong assembly; eight voted against his appointment, while three ballots were invalid.
Židan had been nominated for the office by the incoming government coalition, comprising the Marjan Šarec List (LMŠ), SD, Modern Centre Party (SMC), Alenka Bratušek Party (SAB) and the Pensioners' Party (DeSUS), all of whom amount to a total of 52 votes.
Addressing the National Assembly after being appointed, Židan thanked the MPs for the praise as well as criticism voiced against him. He called on MPs to remain respectful towards each other even when expressing criticism.
"It's up to us to try and raise the level of political culture; to be respectful of each other, not just in this hall but in general."
He wished for MPs to strive for more than just media attention, arguing that sensationalist addresses usually went hand in hand with insults and disrespectful communication.
Prior to the vote, Židan's party colleague Matjaž Han expressed confidence that the new speaker had the experience to guide the National Assembly through the challenges that lay ahead.
Židan is capable of recognising the key goals and implementing them, said Han, adding that the SD party head was one of the few politicians that possessed what he called the feeling for vision on the one hand and a plan on the other.
He also praised Židan's work as agriculture minister, saying that the department was largely responsible for the increase in sales of domestic agricultural products, and highlighted Židan's efforts that led to the UN declaring 20 May World Bee Day.
Branko Grims of the SDS on the other hand was more critical. He said that Židan's fate would be the same as that of the entire emerging coalition which will be a puppet in the hands of the Left, the opposition party that vowed to support the minority government.
Grims accused Židan of being responsible for Slovenia having to allow the use of the Teran protected designation of origin label to Croatia and costing his own party seats in the National Assembly.
What is more, Grims believes that the SD has more capable people for the job than Židan among its MPs.
The opposition National Party (SNS) expressed support for Židan. However, its president Zmago Jelinčič said that Židan will need a lot of energy, and nerves of steel "to survive everything served to him by the gentlemen of the radical left".
"They will not be gentle with him and he will be extorted at every step," said Jelinčič who believes that Židan will respect the parliament's rules and procedures and will treat the left-leaning and the right-leaning parties equally.
The SMC, DeSUS and SAB also expressed support for Židan, while other parties did not take part in the debate ahead of the vote.
Following the session, Židan commented on the apparent failure of the coalition to provide the votes of all of its 50 MPs. He said that he would not be "looking for the missing votes because the coalition, with the support of the opposition, ensured more than 46 votes".
Ballots had not been handed out to Branislav Rajić of the SMC and Franc Kramar of SAB, who were not at the session, their parties told the STA. Franc Trček of the Left was also not at the session, according to his party. Also absent was Zvonko Černač of the SDS.
Židan also told the press that the priority now is to set up parliamentary working bodies to allow the formation of the government.
The new speaker has already received congratulations from President Borut Pahor, outgoing Prime Minister Miro Cerar and Prime Minister-designate Marjan Šarec, among others.
Before the 3 June election, Židan was seen as a possible candidate for prime minister, given that the SD was among the top three parties in the public opinion polls.
He has served as agriculture minister under Pahor, Bratušek and Cerar. Prior to that he served as the boss of Panvita, one of the country's biggest food groups, for three years.
In order for Židan to be appointed speaker today, the MPs had to appoint two deputy speakers so that Tonin was able to step down: Tina Heferle from the ranks of LMŠ and Jože Tanko of the SDS.