After meeting members of the Church of Jesus Christ of Latter-day Saints at an 1846 Philadelphia conference, Kane offered to help in their conflicts with the US government as they tried to migrate West.

During 1857 and 1858, Kane attempted to mediate a dispute between the Latter-day Saints and the US government, persuading Young to concede his governorship to President Buchanan's appointee, preventing further escalation of the Utah War.

After his promotion of brigadier general of volunteers, he journeyed by railroad and buggy to convey intelligence about Robert E. Lee's Gettysburg Campaign.

[5]: 266 As a young man, he expressed interest in a political career and sought a position in the government of California at the conclusion of the Mexican–American War (1848), but was unsuccessful.

[7]: 272  He maintained a correspondence with Horace Greeley and Ralph Waldo Emerson, and wrote newspaper articles on abolition and social issues related to members of the Church of Jesus Christ of Latter-day Saints.

[1]: 57 [9]: 239 With the help of his father, Kane obtained US government permission for the refugee Mormons to occupy Pottawattamie and Omaha Indian lands along the Missouri River.

[2]: 18 [10]: 36  After carrying dispatches relating to the land agreements and battalion criteria to Fort Leavenworth, Kane sought out Little in the Latter-day Saint encampments on the Missouri River.

On July 17, 1846, a meeting was held with Kane, LDS leaders, and Army Captain James Allen to create the Mormon Battalion.

[9]: 242  Miller's Hollow, the principal Iowa settlement of the LDS group at the site of present-day Council Bluffs, was renamed Kanesville in recognition of his service.

Although good care from both an army physician from Fort Leavenworth and church members helped him recover, he suffered poor health the rest of his life.

[11]: 138 In March 1850, in the midst of debate over establishing Utah Territory, Kane delivered an important lecture before the Philadelphia Historical Society.

[2]: 47  He described the religion of the Latter-day Saints, their conflicts with other settlers, and the desolation he witnessed during a visit to the recently abandoned Nauvoo, Illinois.

One thousand copies of the lecture, with associated notes and materials, were printed and distributed, primarily to members of Congress and influential men in the Executive Branch.

The lecture was reprinted in several Mormon publications: the Frontier Guardian (August 7, 1850), and in the Millennial Star (April 15 to July 15, 1851) where it reached an even larger audience.

[18] In a work produced in 1902, historian William Alexander Linn, evidently believing that no non-Mormon would serve as an advocate for the group, asserted that Kane was a secret member of the LDS church and dated his baptism to his 1846 stay on the Missouri River.

[2]: 149  Responding to rumors (later proved false) that the Mormons were in rebellion against the US government, Buchanan sent an army of 2,500, with orders to place Cummings in Young's Governor Office by force if necessary.

[21]: 45 Unfortunately, Buchanan did not officially notify Young about the change in appointment, and rumors of planned US army attacks on Utah communities flew just ahead of the troops.

[2]: 107  Kane persuaded Young to accept Buchanan's appointment of Cumming as Territorial governor, and to present no opposition to the federal troops, called Johnston's Army, acting as escort.

The army came into Utah some weeks later and was bivouacked on vacant land that became Camp Floyd, 30 miles (48 km) southwest of Salt Lake City.

They traveled throughout the territory and were Young's guests at his winter home in St. George, partially in an effort to regain Kane's failing health.

[23] During the winter, Kane and Young laid plans for the Mormon settlement of sections of Arizona and the Sonora Valley in Mexico.

Her father, William Wood, later published selected letters as a book titled Twelve Mormon Homes, since issued in several editions.

[26] Kane returned to Utah upon Young's death in 1877, attending his funeral and offering condolences to family and church leaders.

[2]: 191 [6]: 160  The men in the regiment built three large log rafts and one smaller one, and floated down the Susquehanna River to Harrisburg, where they were mustered in.

When he tried to rise after the fighting was over, a Confederate soldier broke his breastbone with a blow from the butt of his rifle and Kane, unconscious, was captured.

[6] Kane was promoted to brigadier general of volunteers on September 7, 1862, and given command of the 2nd Brigade, 1st Division, XII Corps of the Army of the Potomac.

His men did not participate in the bloody fighting of July 2 because his division, commanded by Maj. Gen. John W. Geary, was pulled out of the line and sent to defend against Confederate attacks on the Union left.

However, when his men returned to their hastily constructed breastworks on Culp's Hill that night, they found Confederate soldiers occupying them and Kane's corps commander ordered an assault for early the next morning to regain the position.

During the action Kane fell ill, and the brigade's second-in-command, Colonel George A. Cobham, Jr., actively assisted in command.

[6]: 161 After the Civil War, Kane and his wife moved to the frontier in western Pennsylvania, eventually owning over 100,000 acres (400 km2) of timberland on which oil and gas were later discovered.