Ever since Crocker was young, he's always been interested in politics and started his political career in 2261 as a local mayor for the NCR. From there, he managed then General Aaron Kimball's first run for a seat on the Council. Because of his support of President Kimball's political career, Crocker was given ambassadorship to New Vegas as the successor to Susanna Edith. Crocker is a strong believer in diplomacy and hopes to unite the Mojave Wasteland under the NCR peacefully. However, his work has made very little progress since Mr. House refuses to even meet him in person.
Things That Go Boom: Crocker wants you to start diplomatic ties with the Boomers. After you finish the quest Volare! and have become idolized by the Boomers, you can speak to Pearl and ask her for support during the Battle of Hoover Dam. Once it is done, you can return to Crocker and tell him that the Boomers are now on NCR's side.
When you first leave the Lucky 38, you will receive a letter from Crocker delivered by an NCR soldier. In the letter he requests that you come speak to him at the NCR Embassy, agreeing to pardon you of any crimes you may have committed against the NCR up to that point.
Killing Crocker (even while hidden & equipped with a Stealth Boy), will cause NCR infamy as well as the soldiers inside the Embassy & outside the Strip to become hostile towards the player. Also, killing Crocker will start the quest Don't Tread on the Bear! (if not already given this quest), only to immediately be failed by default, due to his death. (You are then seen as a 'terrorist' to the NCR)
Crocker wears a boutonnière, the state flower of California.
Some NCR troops in Vegas seem to have a very low opinion of him, most likely due to his pacifist views.
Ambassador Crocker claims he has had the position for 7 years and that he is the 3rd ambassador, following Phillip Granger and Susanna Edith (served 2 years), yet the treaty itself is only 7 years old and Mr House only organized the Families right before it. So there is a discrepancy in the timeline here.
Crocker will bet the most caps of any non-player character in the game while playing Caravan.
In the quest Kings' Gambit, after learning from Rotface that Pacer has a jet addiction, return to the embassy. After telling Crocker this information, you'll have a special dialog option for Wild Wasteland, which causes Crocker to shout "DAMN IT, I'M AN AMBASSADOR, NOT A DOCTOR!" This is a reference to a commonly mis-attributed Star Trek quote from Bones McCoy, Damn it, I'm a Doctor not a ....
The name "Crocker" is not a reference to Ryan Crocker, a US ambassador to Iraq and Afghanistan.
Dennis Crocker was originally intended to be a Caucasian male, however, due to an error, a non-Caucasian voice actor recorded his lines. The character's appearance was altered accordingly.
PCPlayStation 3Xbox 360 If the Courier waits in the Embassy at night when Ambassador Crocker isn't around, waiting for him to appear in the morning/afternoon, he will not appear in the building. All you have to do is take your player and exit the Embassy and re-enter for the Ambassador and his secretary to appear in the Embassy. He will not always reappear though, sometimes disappearing from the game permanently.
On the PC, this can be corrected by opening the console and entering prid 116840, followed by enable.
Alternately, open the console and enter player.placeatme 00112640
Xbox 360 Upon completing "Things That Go Boom" if you become idolized by the NCR a random MP will act as the male assassin for one who does wrong towards the NCR. He will complete his line and then attack you. Killing him does not cause infamy.
PlayStation 3 When the Courier would like to know more about the NCR, when having a negative reputation(merciful thug), the spoken text is not the same as the text on the screen.
If Ambassador Crocker is killed with the console you will gain infamy, similar to after Aaron Kimball's assassination.