Yes, your Beneficiary may be one of your Executors and it is quite common for this to happen. A common arrangement is for a husband and wife to be both the Primary Beneficiary and Executor appointed in each other’s Wills.
Due to the personal nature of the duties that an Executor undertakes, you should appoint someone that you trust to carry out the process; this will quite often be someone who is also a Beneficiary. Some of the tasks of the Executor include (but are not limited to); taking care of funeral arrangements, organising your estate and everything you own for distribution to your Beneficiaries and paying off any debts and outstanding taxes that you may have owed upon your death.
It is important that the Executor/s appointed will also be of a sound mental state at the time to be able to carry out your wishes and also generally able to do so. It is one thing to trust someone to be handling your personal affairs, but they need to also be able to carry out the task. In most instances, there will be two Executors appointed to a Will so the Executor work and decision making is shared. Also in case that one of the Executors passes before you, there will still be one appointed and left to carry out the tasks of administering your Will. You might arrange it, for example, so that your partner as an Executor will handle all the very personal details such as funeral arrangements and organising your estate, and other Executor who will be suitable for handling the more financial and legal side of things such as paying off debts and taxes, distributing the estate and acting as a Trustee if required. There are a number of ways you can arrange Executor duties and the choice is up to you.
However, it is important to note that with a very large estate and/or one that will require Trustee arrangements, it is recommended that you consult a solicitor to ensure you have set up your Will and estate correctly, according to legislation and to avoid any problems for your Beneficiaries.
Problems can arise though when there are disagreements between the Beneficiaries themselves. A Beneficiary who is the Executor does have the upper hand and disagreements can result in costly and sometimes lengthy court cases. Of course, this is not usually the case but should be taken into consideration when appointing Executors.
In any case, there is no rule about who can and cannot be appointed as your Executor of your Will, only that they be over the age of 18 years, of sound mind and able to carry out your wishes and any decisions responsibly. The decision on who will be appointed the Executor of your Will rests entirely with you and your wishes. In most cases the Executors will require legal help to administer your Will and if at the time an Executor is unable or unwilling to carry out the duties, they have the option to hand it over to legal representation to act on their behalf.