Subjective Case of Pronouns
Pronouns are also used as subjects of verbs. Use the subjective case of pronouns when the pronoun is the subject of a verb.
I drive to work.
He enjoys dancing.
We bought the lodge.
They are fighting over the property line.
The player who won the game was the guest of honor.
When there are compound subjects—that is, more than one actor—don't be confused. Pronouns should still be in the subjective case.
Eileen and he (not Eileen and him) enjoy dancing.
The Harrisons and they (not The Harrisons and them) are fighting over the property line.
To keep from making pronoun case errors in sentences with compound subjects, drop the subject that is a noun and read the sentence with the pronoun alone. You would never say Him enjoy dancing or Them are fighting over the property line. When you apply this test, you'll see that the subjective forms he and they are correct.
Pronouns following “to be”
You should also use the subjective case of pronouns after forms of the verb to be.
It is I who chose the location.
The man who called the police was he.
The real criminals are we ourselves.
The winners were they and the Rudermans.
The man who phoned was who?
The word after a form of to be is called a complement. It is also sometimes called a predicate nominative or predicate adjective.
Unlike words following action verbs, the complement of a linking verb is not an object, a receiver of action. Instead, the complement identifies or refers to the subject. Compare the following two sentences.
The president saw Mr. Komino.
The president was Mr. Komino.
In the first sentence, Mr. Komino is an object that receives the president's action of seeing. If a pronoun were to be substituted for Mr. Komino, the pronoun would be in the objective case: him. But in the second sentence, Mr. Komino isn't receiving any action. Mr. Komino identifies the subject: the president. The correct pronoun to substitute for Mr. Komino in this sentence would be he.
Pronoun complements can cause case problems. As the rule says, the subjective form of a pronoun is correct after to be, but sometimes it sounds unnatural or too formal.
It is I.
I am she.
The person I chose was he.
The winners were they.
The best way to handle awkward‐sounding constructions is to look for a better way to say the same thing. For example:
They were the winners.
OR They won. (better)
He was the person I chose.
OR I chose him. (better)
In informal speech and writing, modern usage allows It is me or It's me. In formal writing, either stay with the established rule or rewrite the sentence to avoid correct but awkward wording.