First, middle, and last name must be the same.
Michael John Smith has a son he names Michael John Smith. The son can be Michael John Smith, Jr., or Michael John Smith II. Regardless if he is called Jr. or II, if his son is also Michael John Smith, he will be III.
If Michael John Smith II has a son named Michael John Smith, that son would be III. If Michael John Smith I is no longer living, then Michael John Smith II chould call himself Michael John Smith, Sr, and his son Smith, Jr. If Jr (MJS III) has a son named MJS IV, and JMS, Sr, is no longer living, MJS III can change fro being Jr to being Sr and MJS IV can be called Jr.
The cardinal numbering, and the use of Jr/Sr, may also be used in grandfather-grandson and uncle-nephew relationships. For example:
Michael John Smith has a son he names Robert Phillip Smith. Robert has a son he names Michael John Smith II after his grandfather.
Michael John Smith has two sons, one named Robert Philip Smith, the other James Richard Smith. Robert Philip Smith has a son he names James Richard Smith II after his uncle.
The III designation would be used if naming a boy after any of the above IIs.
Short form for Junior
Naming people "Sr." and "Jr." is a separate system from naming them "Second," "Third," "First," etc. Commonly, John Doe, Jr. can drop the "Jr." from his name after John Doe, Sr. dies, but he does not have to. For example, Sammy Davis, Jr., the famous black entertainer, continued to use "Jr." for many years after his father, Sammy Davis, Sr., died. He did, eventually, call himself simply, Sammy Davis. Naming people "I," "II," "III," etc. is a completely separate system and does not even require that III be the son of II. John Doe III could be the son of Jason Doe, and the nephew, younger cousin, or other relative of John Doe II, as long as both are recognized as being in the same family. The numbering does not change when one of them dies. John Doe IV, the son of John Doe III and the grandson of John Doe II, will always be John Doe IV, even after I, II and III have died. He may as a matter of convenience, choose to drop the number, or, if he has a son named John Doe V, he might choose to be John Doe, Sr., to his son's John Doe, Jr.
A suffix is a part of a larger word; for example, in the word helpless, "less" is a suffix. Jr. is just part of the name, not a suffix, since it is not attached to any other word. However, names can have prefixes or suffixes. For example, John McCain, the "Mc" is a prefix, attached to the word. In Icelandic, you can have names such as "Siggurdsdottir" in which "dottir" is a suffix (meaning, the daughter of).
If Jason James, Jr., has a son named Jason James, and Jason James, Sr. is still living, the grandfather can continue to use the suffix, "senior." The grandson, cannot be called "junior" because his father still has that suffix, but the grandson may be called Jason James III, if the grandfather was the first in the family to be called Jason James.
Normally the III means that "John Doe III's" father and grandfather are named (grandfather) "John Doe Sr." and (father) is named "John Doe Jr.". Which would change their names to "John Doe I" and "John Doe II" when "John Doe III" is named. The naming can also skip a generation or even a nephew or grandnephew can continue the name. I have seen the use of the roman numeral system with female names also.
When "Jr" or "Sr" follows a last name, it is called a suffix or a generational suffix. It is used to indicate that a person has the same name as their father or grandfather respectively.
Suffixes like Jr., Sr., II, III, etc. are typically added after the last name when listing names. For example, John Smith Jr.
A suffix on a job application refers to letters added at the end of a name to further define it, such as Jr., Sr., III, or PhD. It provides additional information about the individual's identity or familial relationships.
If she is his sister or his daughter, her surname would also be "JR". However, I believe that you are referring to the generational suffix of "Jr.", meaning "Junior". In that case, a woman who chooses to retain her maiden name and prefers the title "Ms." also retains the very cunning linguistic freedom to use the generational suffix of "Jr." or "II" (the second).
Short form for Junior
It's called the suffix, and is more a title than a part of a name.
This would be the Sr. Jr. or III after your name. Most students do not have this on their name and would leave it blank.
Some people continue to use Jr after Sr has died, others do not. Numbering is a completely separate system and does not change when an earlier number dies. John James I is usually the father of John James II but could be an uncle or other older relative. At some point John James II could be John James, Sr to John James III as John James, Jr. Later, after John James II dies, John James III can be Sr to John James IV as Jr. And so forth.
When typing last names first, the suffix (such as Jr., Sr., III) typically follows the last name, before the first name. For example, Smith Jr., John.
no.
I suppose you mean suffix in the context of name. Example: Last Name, First Name, Middle Initial, Suffix This would refer to things like Jr., Sr, of III James A. Smith, III (The suffix would be III) Richard B. Jones, Jr. (The suffix would be Jr.)
A man with the same name as his father remains a Jr. his son would be III. II is only used for naming a son after ANOTHER family member such as an uncle or grandfather and ONLY when all names are exactly the same (FIRST MIDDLE LAST). A Junior never becomes a II. Try explaining "it's automatic" to the Soc Sec Admin, IRS, your employer, and countless others who have legal documents with your Jr. on record. I guess you could LEGALLY change your suffix from Junior to II but why?!?! It is not consistent with genealogical nor historical precedent.