Essential Job Functions: A Core Defense in Disability Claims

FEHA doesn’t require a California employer to keep someone in a job they can’t do, even with accommodation. The California Supreme Court held in Green v. State of California (2007) 42 Cal.4th 254 that “the plaintiff employee bears the burden of proving he or she was able to do the job, with or without reasonable accommodation.” What counts as “the job” is defined by its essential functions. An employer that can prove those functions with documents prepared before the dispute starts out in a much stronger position.

What are essential job functions under California law?

The fundamental duties of the position, not the marginal ones.

Government Code section 12926(f) defines “Essential functions” as “the fundamental job duties of the employment position the individual with a disability holds or desires,” and says the term “does not include the marginal functions of the position.” The statute lists reasons a duty may be essential, including that the position exists to perform it, there are few employees available to share it, or it takes skills the employee was hired for.

The Civil Rights Council’s regulation describes the other side of the line. Under 2 CCR section 11065(e)(3), “Marginal functions” are duties “that, if not performed, would not eliminate the need for the job or that could be readily performed by another employee or that could be performed in an alternative way.” That definition matters in accommodation disputes. A duty an employer could easily reassign is a poor basis for saying an employee can’t do the job.

Who has to prove the employee could do the job?

The employee.

In Green, a stationary engineer at a state prison with hepatitis C won a jury verdict on a FEHA disability discrimination claim. The jury was never instructed on whether the employee could perform the job’s essential duties, and the Court of Appeal said the burden was on the employer. The Supreme Court disagreed. It held that “drawing these distinctions is prohibited only if the adverse employment action occurs because of a disability and the disability would not prevent the employee from performing the essential duties of the job, at least not with reasonable accommodation.”

The court’s conclusion was direct: “a plaintiff must demonstrate that he or she was qualified for the position sought or held in the sense that he or she is able to perform the essential duties of the position with or without reasonable accommodation. Juries should be so instructed.” The court reversed and remanded.

That allocation is where the defense starts. The statute itself, in section 12940(a)(1), says FEHA does not prohibit discharging an employee who “is unable to perform the employee’s essential duties even with reasonable accommodations.” Green confirms that the employee carries the burden of showing that isn’t the case.

Can a duty be essential if it’s rarely performed?

Yes, if the employer has a legitimate need for everyone in the role to be able to do it.

Lui v. City & County of San Francisco (2012) 211 Cal.App.4th 962 involved a police officer who had suffered a major heart attack and sought an administrative assignment. The department required every full duty officer, including those in desk jobs, to be able to make forcible arrests and chase suspects. After a court trial, judgment went to the city, and the Court of Appeal affirmed.

The court concluded that “even though officers in administrative positions are not frequently required to engage in such activities, the strenuous duties are essential functions of the positions because the Department has a legitimate need to be able to deploy officers in those positions in the event of emergencies and other mass mobilizations.” The deciding factor was staffing. “Because the Department only has a limited number of full duty officers,” the court explained, “for each officer in a modified-duty assignment, there is one less officer available to be deployed in an emergency.”

Lui also shows what that defense takes. The department had a written list of essential job functions, testimony about real mobilizations, and staffing numbers. The opinion called the identification of essential functions a “highly fact-specific inquiry.” A private employer making the same argument without that kind of record would have a much harder time.

What evidence proves a function is essential?

The employer’s judgment, backed by documents created before the dispute.

Section 12926(f)(2) lists the evidence. The regulation in section 11065(e)(2) adds two items, current job descriptions and prior performance reviews.

The written job description is where employers most often lose this argument. The statute gives weight to descriptions “prepared before advertising or interviewing applicants for the job.” A description drafted after an employee asks for accommodation reads as a litigation document. One written years earlier, reviewed periodically, and signed by the employee at hire is evidence a court will take seriously.

How does the essential functions defense fit with the duty to accommodate?

It sets the target the accommodation has to hit.

Under the regulation’s definition, a reasonable accommodation is one “effective in enabling an employee to perform the essential functions of the job the employee holds or desires.” So the employer has to explore whether the employee can perform each essential function with help, and whether marginal duties can be reassigned. That exploration happens in the interactive process, which the firm covers in its post on failure to engage in the interactive process. An essential functions defense is strongest when the record shows the employer identified the functions, discussed them with the employee, and looked at accommodations aimed at each one before concluding the employee couldn’t do the job.

There’s a separate defense in the same statute. Section 12940(a)(1) also permits action against an employee who “cannot perform those duties in a manner that would not endanger the employee’s health or safety or the health or safety of others even with reasonable accommodations.” Safety cases need their own medical evidence, and the employer should treat that as a separate showing.

Steps to take when an employee says they could do the job

1. Preserve the job description and every prior version, the employee’s performance reviews, medical restrictions, interactive process notes, and staffing records, under a litigation hold once a claim arrives.
2. Calendar the response date on the CRD complaint, demand, or summons, and check for an arbitration agreement and an EPLI policy with notice requirements.
3. Identify the managers who can explain why each disputed duty is essential, and stop any further action against the employee that could look like retaliation.
4. Pull the documents the defense depends on: when the job description was written, how often incumbents perform the duty, and what accommodations were considered for each essential function.
5. Talk to a lawyer before responding, contacting the employee or their lawyer, or offering anything to settle.

Disputes over what a job requires are common in employment defense for California businesses, and the job description is often the first exhibit.

FAQ

Does a job description automatically decide which functions are essential?

No. It’s one piece of evidence among several, and a court weighs it alongside time spent on the duty, the consequences of not performing it, and the experience of people in the role. But a description written before the position was advertised, and kept current, carries real weight. Employers should review descriptions periodically so they match what the job actually requires.

Can an employer require a duty the employee has never actually performed?

Possibly. In Lui, administrative officers rarely made arrests, but the court still treated those duties as essential because the department needed every full duty officer available for emergencies. That holding depended on concrete staffing evidence. An employer relying on a rarely performed duty should be ready to show why the duty can’t be spread among other employees.

What if the employee could do the job with an accommodation?

Then the employee may be a qualified individual, and the employer’s focus shifts to whether the accommodation is reasonable or would impose undue hardship. Essential functions still define the analysis, because an accommodation has to enable the employee to perform them. An arrangement that just eliminates an essential function doesn’t fit that definition.

Does the essential functions defense apply to failure-to-accommodate claims too?

Yes. California courts have applied the same requirement to accommodation claims. In Lui, the court explained that to prevail on both claims, the plaintiff had to show the ability to perform the essential functions of the positions sought, with or without reasonable accommodation. The same evidence supports the defense to both causes of action.

If an employee claims they could have done the job

If your company has received a CRD complaint or lawsuit from an employee who says a disability didn’t prevent them from doing the job, the job description and the essential functions record usually decide how strong the claim is. Rosenberger + Kawabata represents employers defending employment lawsuits and claims through its business litigation practice, including disability discrimination claims that turn on essential job functions. Contact Rosenberger + Kawabata online for a confidential consultation, or call (310) 894-6921.

Sources

Government Code sections 12926 and 12940; California Code of Regulations, title 2, section 11065; Green v. State of California (2007) 42 Cal.4th 254; Lui v. City & County of San Francisco (2012) 211 Cal.App.4th 962.

This post is general information about California and federal employment law as of November 7, 2026. It is not legal advice, and reading it does not create an attorney-client relationship. Employment statutes, regulations, and court decisions change often, and the outcome of any claim depends on its facts. Past results do not guarantee future outcomes.