Colombo entered politics as a member of the Christian Democracy in 1948.
He was firstly elected to the parliament in 1948.
Having held several cabinet posts, he served as the prime minister of Italy from 1970 until his resignation in 1972.

A number of progressive reforms were introduced during Colombo's time as prime minister.
A housing reform law of 22 October 1971 introduced new criteria for land expropriations and provisions for urban renewals.
Under a law of 6 December 1971, state funds were made available for the construction of a kindergarten in every local authority.
A law of 30 December 1971 introduced new regulations covering protection of female workers and maternity insurance.
 The duration of maternity leave was extended two months prior to, and two months after confinement for all employees, and all female workers were entitled to an earnings-related indemnity, equal to 80% of earnings (including agricultural workers and tenant farmers).
Also introduced was an entitlement to voluntary extra period of leave for six months during the first year of the child’s life, with job security and an indemnity equal to 30% of earnings, together with an entitlement to paid absences due to the child’s sickness during the first three years if the child’s life.
In addition, a special natality allowance was introduced for self-employed women in the agricultural, artisan, and commercial sectors.

Later he became president of the European Parliament (occupying that office from 1977 until 1979) and foreign minister of Italy (from 1980 until 1983, and again from 1992 until 1993).
In February 2003 then president Carlo Azeglio Ciampi bestowed Italy's highest political honour on him, by nominating him Senator for life.

After the inconclusive elections on 24–25 February 2013 and the following difficulties of the hung Senate in electing a presiding officer, Colombo became acting speaker of the Senate, being the most senior member, until the election of Pietro Grasso on 16 March 2013.

After the death of Giulio Andreotti on 6 May 2013, Colombo became the last surviving member of the Italian Constituent Assembly.
Colombo entered politics as a member of the Christian Democracy in 1948. He was firstly elected to the parliament in 1948. Having held several cabinet posts, he served as the prime minister of Italy from 1970 until his resignation in 1972.
A number of progressive reforms were introduced during Colombo's time as prime minister. A housing reform law of 22 October 1971 introduced new criteria for land expropriations and provisions for urban renewals. Under a law of 6 December 1971, state funds were made available for the construction of a kindergarten in every local authority. A law of 30 December 1971 introduced new regulations covering protection of female workers and maternity insurance.  The duration of maternity leave was extended two months prior to, and two months after confinement for all employees, and all female workers were entitled to an earnings-related indemnity, equal to 80% of earnings (including agricultural workers and tenant farmers). Also introduced was an entitlement to voluntary extra period of leave for six months during the first year of the child’s life, with job security and an indemnity equal to 30% of earnings, together with an entitlement to paid absences due to the child’s sickness during the first three years if the child’s life. In addition, a special natality allowance was introduced for self-employed women in the agricultural, artisan, and commercial sectors.
Later he became president of the European Parliament (occupying that office from 1977 until 1979) and foreign minister of Italy (from 1980 until 1983, and again from 1992 until 1993). In February 2003 then president Carlo Azeglio Ciampi bestowed Italy's highest political honour on him, by nominating him Senator for life.
After the inconclusive elections on 24–25 February 2013 and the following difficulties of the hung Senate in electing a presiding officer, Colombo became acting speaker of the Senate, being the most senior member, until the election of Pietro Grasso on 16 March 2013.
After the death of Giulio Andreotti on 6 May 2013, Colombo became the last surviving member of the Italian Constituent Assembly.
Emilio Colombo