[3][4] In the 2019 election, Altomare defeated Progressive Conservative (PC) incumbent Blair Yakimoski to become the Member of the Legislative Assembly for the district of Transcona.

In the 42nd Manitoba Legislature, Altomare served as the NDP's critic for education and early childhood learning.

He was appointed to serve as minister for the same portfolio after the NDP replaced the PCs as the governing party in the 2023 Manitoba general election.

[2] As Minister, he oversaw the creation of a searchable online database of Manitoban teachers as part of an effort to increase transparency around misconduct in education.

[4] He also oversaw the passing of legislation to create a permanent universal school food program, which Premier Wab Kinew said would be named "Nello's Law".