Nominated by Republican President Rutherford B. Hayes, King was noted for his exploration of the Sierra Nevada mountain range.

That summer, he and several friends borrowed one of Yale's rowboats for a trip along the shores of Lake Champlain and a series of Canadian rivers, then returned to New Haven for the fall regatta.

King began to read more about geology, attended a lecture by Louis Agassiz, and soon wrote to Brush that he had "pretty much made up my mind to be a geologist if I can get work in that direction".

[citation needed] In late 1862 or early 1863, King moved to New York City to share an apartment with James Terry Gardiner, a close friend from high school and college (who spelled his last name Gardner at the time).

In February 1863, King became one of the founders, along with John William Hill, Clarence Cook and others, of the Ruskinian Association for the Advancement of Truth in Art, an American group similar to the Pre-Raphaelite Brotherhood, and was elected its first secretary.

[13][7][14] As Gardiner and King started to quickly plan for the journey,[8] their final destination being San Francisco,[15] another friend named William Hyde became interested and decided to join them.

Near Fort Kearny, 200 miles into their journey, King tried hunting buffalo, but he did not succeed and ended up with a wounded leg and a dead horse.

[18] On May 29, the traveling party passed the very large 325-foot landmark called Chimney Rock in northwest Nebraska and a few days after that they arrived at Fort Laramie in what is now Wyoming.

[22] That night the foundry caught on fire burning everything the three guys owned, including King's letter to William Henry Brewer at the California Geologic Survey.

As they helped rebuild the foundry King and Gardiner were able to save up enough supplies to continue on while Hyde decided to stay with his father.

Planning to walk the rest of the way by foot, Gardiner and King left Gold Hill near the end of August 1863.

[25] Once Gardner and King arrived at the California Geological Society's office, they met the director of the survey Josiah Whitney.

[26] In 1863, with the permission of Whitney, King was asked by Brewer to accompany him on his exploration of the northern part of the Sierra Nevada Mountain range.

[27] As the group traveled, they passed through the Sierra gold fields, and at a creek named Genesee, Brewer found fossils of the Jurassic or Triassic age.

[29] At nights around the campfire, geologic concerns such as the young Cascade volcanoes, the age of gold veins, and the action of glaciers was discussed.

[31] During this job, King had a habit of staring at views as opposed to working like he was supposed to which irritated his fellow team members.

[38] In King's own words, "It was a trying moment for Brewer when we found him and volunteered to attempt a campaign for the top of California, because he felt a certain fatherly responsibility over our youth.

During this King got permission to attempt to climb Mount Whitney again but he had to rendezvous with the main group in two weeks at Clark's Station.

[44] Both Gardner and King were unpaid volunteers for this expedition, but they had helped create the first topographic, botanical, and geologic survey of a vast area.

King suffered from several bouts of malaria in the spring and summer of 1865 while Whitney, also in the East, worked on securing funding for further survey projects.

He persuaded Gardiner to be his second in command and they assembled a team that included, among others, Samuel Franklin Emmons, Arnold Hague, A. D. Wilson, the photographer Timothy H. O'Sullivan and guest artist Gilbert Munger.

He took the position with the understanding that it would be temporary and he resigned after twenty months, having overseen the organization of the new agency with an emphasis on mining geology.

He had a busy social life, with close friendships including Henry Brooks Adams and John Hay, who admired him tremendously.

[56] In his scientific reflections, he would vividly explain natural things that he encountered in his adventures in an artistic manner, blending the two subjects together.

As interracial marriage was strongly discouraged in the nineteenth century, and illegal in many places, King hid his identity from Copeland.

Despite his blue eyes and fair complexion, King convinced Copeland that he was an African-American Pullman porter named James Todd.