In fall 1854, he moved with his bride, Caroline Joy French, to the Nebraska Territory, and in 1855 purchased 160 acres in Nebraska City.
Soon after arriving there, Morton became the editor of the local newspaper, the Nebraska City News.
 Morton served briefly in the Nebraska Territorial House of Representatives (1855–1856).
 He was appointed Secretary of Nebraska Territory by President James Buchanan on July 12, 1858, a position he held until 1861.
 Morton also served as Acting Governor of Nebraska from December 5, 1858, to May 2, 1859.

Morton built a 30-room mansion.
His son, Joy, expanded it to a 52-room mansion that is a look-alike of the White House in what is now Arbor Lodge State Historical Park, Nebraska City, Nebraska.
On the surrounding estate, Morton indulged his fascination with trees, planting many rare varieties and heirloom apple trees.
 Respected as an agriculturalist, Morton sought to instruct people in the modern techniques of farming and forestry.
Among his most significant achievements was the founding of Arbor Day.
He is also remembered for his support of slavery and his fierce opposition to cutting down healthy trees as Christmas decorations.
He became well known in Nebraska for his political, agricultural, and literary activities and from there was appointed as United States Secretary of Agriculture by President Cleveland (1893–1897).
He is credited with helping change that department into a coordinated service to farmers, and he supported Cleveland in setting up national forest reservations.

In 1897, Morton planned and began to edit the multi-volume Illustrated History of Nebraska.
He also began publishing a weekly periodical, The Conservative.
Morton died on April 27, 1902 in Lake Forest, Illinois, where he was seeking medical treatment; his wife, Caroline, had died two decades earlier, in June 1881.
 The Morton home and estate in Nebraska City is now a state park, the Arbor Lodge State Historical Park and Arboretum.

In 1937, the state of Nebraska donated a bronze statue of Morton to the National Statuary Hall Collection at the United States Capitol.
Morton is a member of the Nebraska Hall of Fame.
The J. Sterling Morton Beltway, a highway near Nebraska City, Nebraska, which is made up of U.S. Route 75 and Nebraska Highway 2, is named for him.
J. Sterling Morton Magnet Middle School in Omaha, Nebraska, also bears his name, as do Morton College (a community college) and J. Sterling Morton High School District 201 in Berwyn and Cicero, Illinois.

His son Joy Morton was the founder of the Morton Salt Company, Chicago, Illinois.
 The son also created The Morton Arboretum in Lisle, Illinois in 1922.
 Today, Joy Morton's original 400-acre (1.6 km²) Thornhill Estate, which he acquired in 1910, has been transformed into a 1,700-acre (6.9 km²) living history museum of over 4,000 different types of trees, shrubs and other woody plants.

Although Morton was a "Bourbon" (i.e. conservative) Democrat, his son Paul Morton served as Secretary of the Navy under President Theodore Roosevelt from 1904 to 1905 as a Progressive Republican.
In fall 1854, he moved with his bride, Caroline Joy French, to the Nebraska Territory, and in 1855 purchased 160 acres in Nebraska City. Soon after arriving there, Morton became the editor of the local newspaper, the Nebraska City News.  Morton served briefly in the Nebraska Territorial House of Representatives (1855–1856).  He was appointed Secretary of Nebraska Territory by President James Buchanan on July 12, 1858, a position he held until 1861.  Morton also served as Acting Governor of Nebraska from December 5, 1858, to May 2, 1859.
Morton built a 30-room mansion. His son, Joy, expanded it to a 52-room mansion that is a look-alike of the White House in what is now Arbor Lodge State Historical Park, Nebraska City, Nebraska. On the surrounding estate, Morton indulged his fascination with trees, planting many rare varieties and heirloom apple trees.  Respected as an agriculturalist, Morton sought to instruct people in the modern techniques of farming and forestry. Among his most significant achievements was the founding of Arbor Day. He is also remembered for his support of slavery and his fierce opposition to cutting down healthy trees as Christmas decorations. He became well known in Nebraska for his political, agricultural, and literary activities and from there was appointed as United States Secretary of Agriculture by President Cleveland (1893–1897). He is credited with helping change that department into a coordinated service to farmers, and he supported Cleveland in setting up national forest reservations. 
In 1897, Morton planned and began to edit the multi-volume Illustrated History of Nebraska. He also began publishing a weekly periodical, The Conservative. Morton died on April 27, 1902 in Lake Forest, Illinois, where he was seeking medical treatment; his wife, Caroline, had died two decades earlier, in June 1881.  The Morton home and estate in Nebraska City is now a state park, the Arbor Lodge State Historical Park and Arboretum.
In 1937, the state of Nebraska donated a bronze statue of Morton to the National Statuary Hall Collection at the United States Capitol. Morton is a member of the Nebraska Hall of Fame. The J. Sterling Morton Beltway, a highway near Nebraska City, Nebraska, which is made up of U.S. Route 75 and Nebraska Highway 2, is named for him. J. Sterling Morton Magnet Middle School in Omaha, Nebraska, also bears his name, as do Morton College (a community college) and J. Sterling Morton High School District 201 in Berwyn and Cicero, Illinois.
His son Joy Morton was the founder of the Morton Salt Company, Chicago, Illinois.  The son also created The Morton Arboretum in Lisle, Illinois in 1922.  Today, Joy Morton's original 400-acre (1.6 km²) Thornhill Estate, which he acquired in 1910, has been transformed into a 1,700-acre (6.9 km²) living history museum of over 4,000 different types of trees, shrubs and other woody plants.
Although Morton was a "Bourbon" (i.e. conservative) Democrat, his son Paul Morton served as Secretary of the Navy under President Theodore Roosevelt from 1904 to 1905 as a Progressive Republican.
Julius Sterling Morton