On 1 June 2010, Landini was elected General Secretary of FIOM.
During his secretariat, Landini had a turbulent relationship with FIAT's CEO, Sergio Marchionne, who often criticized for his offshoring policies.
In 2011 he wrote the book "Change the factory to change the world: FIAT, the trade union and the left's absence", published by Simon and Schuster.
It is book-interview about the whole history FIAT and especially, his relationship with Marchionne.
As leader of the metalworkers he was particularly involved in the Ilva affair.

In 2014 Landini became a hard critic and opponent of centre-left Prime Minister, Matteo Renzi.
Tensions rose up due to Renzi's huge labour market reform, called Jobs Act, which provided, among others, the abolition of Article 18 of Workers' Statute, which protected workers from unjustified dismissals.
The proposal was heavily criticised by Landini and CGIL's General Secretary Susanna Camusso, who announced a public protest.
On 25 October, almost one million people took part in a mass protest in Rome, organised by the CGIL in opposition to the labour reforms of the government.
Some high-profile members of the left-wing faction of the Democratic Party also participated in the protest.
On 8 November more than 100,000 public employees protested in Rome in a demonstration organised by the three trade unions.
Despite the mass protests, in December, the Parliament approved the Jobs Act.

In June 2015, Landini launched Social Coalition (CS), a transversal political organization, whose goals were the protection of workers and the middle class.
The organization, that reunited several leftist thinkers, like the jurist Stefano Rodotà, the politician Vittorio Agnoletto, the former communist terrorists Oreste Scalzone and Franco Piperno, never became an official party and was disbanded after few months.

In 2016, he was particularly involved in the 2016 constitutional referendum proposed by Renzi, where voters were asked whether they approve a constitutional law that amended the Italian Constitution to reform the composition and powers of the Parliament of Italy, as well as the division of powers between the State, the regions, and administrative entities.
Landini campaigned for the "No", stating that it was a "badly made reform".
On 4 December, the reform was reject by voters with 59% of votes against and 41% in favor, and Renzi resigned from his post.

On 15 July 2017, Landini left the leadership of FIOM and was succeeded by Francesca Re David.
Four days before, the CGIL's General Assembly approved his appointment in the National Secretariat, with 166 votes in favor, 7 against and 1 abstained.
On 1 June 2010, Landini was elected General Secretary of FIOM. During his secretariat, Landini had a turbulent relationship with FIAT's CEO, Sergio Marchionne, who often criticized for his offshoring policies. In 2011 he wrote the book "Change the factory to change the world: FIAT, the trade union and the left's absence", published by Simon and Schuster. It is book-interview about the whole history FIAT and especially, his relationship with Marchionne. As leader of the metalworkers he was particularly involved in the Ilva affair.
In 2014 Landini became a hard critic and opponent of centre-left Prime Minister, Matteo Renzi. Tensions rose up due to Renzi's huge labour market reform, called Jobs Act, which provided, among others, the abolition of Article 18 of Workers' Statute, which protected workers from unjustified dismissals. The proposal was heavily criticised by Landini and CGIL's General Secretary Susanna Camusso, who announced a public protest. On 25 October, almost one million people took part in a mass protest in Rome, organised by the CGIL in opposition to the labour reforms of the government. Some high-profile members of the left-wing faction of the Democratic Party also participated in the protest. On 8 November more than 100,000 public employees protested in Rome in a demonstration organised by the three trade unions. Despite the mass protests, in December, the Parliament approved the Jobs Act.
In June 2015, Landini launched Social Coalition (CS), a transversal political organization, whose goals were the protection of workers and the middle class. The organization, that reunited several leftist thinkers, like the jurist Stefano Rodotà, the politician Vittorio Agnoletto, the former communist terrorists Oreste Scalzone and Franco Piperno, never became an official party and was disbanded after few months.
In 2016, he was particularly involved in the 2016 constitutional referendum proposed by Renzi, where voters were asked whether they approve a constitutional law that amended the Italian Constitution to reform the composition and powers of the Parliament of Italy, as well as the division of powers between the State, the regions, and administrative entities. Landini campaigned for the "No", stating that it was a "badly made reform". On 4 December, the reform was reject by voters with 59% of votes against and 41% in favor, and Renzi resigned from his post.
On 15 July 2017, Landini left the leadership of FIOM and was succeeded by Francesca Re David. Four days before, the CGIL's General Assembly approved his appointment in the National Secretariat, with 166 votes in favor, 7 against and 1 abstained.
Maurizio Landini