How do a company retain an employee who is a good resource but the team lead seems to be not agreeing because jealousy?

you said a team lead or leader is jealous.

leaders are never jealous,leaders are accomplishers.

my advise,change your team leader.

If a company has a good vision, it will try to sort out the issues by counselling of both employees if possible, otherwise either of them will be shifted to diffrent project or location.

in business especially if the company is not a sole propritorship there are rules govern the relation between employees and the rules of promoting or punishing employees (no emotions) and the role of the management is to follow up applying the rules in every aspect in th company, also the management has the right to relocate the persons as needed

if they are a team work and if both knows what and how they should react according to company result, and that who gets promoted is promoted due to his/her end results on tasks given no one should feel bad or so, otherwise its not professional , simply its busniess nothing personal in there

Team lead is also an "employee" .  he should be referred to HR to make the Team lead understand "he is just another employee and there is no space for personal agony.

Environment is the best working place for all employee, bring a good environment will be satisfied for working of the Organization to success within a short time will benefit both sides.

It is very important for an organization to retain an old employee. The old employee may have problems with his supervisors for many reasons. As the employee is tenured it is possible that his/her super visor was his own college who got promoted which the old employee may think unfair to him. This may the main cause of the conflict. The supervisor should be asked by the manager to handle the tenured resource more carefully. But if the conflict continues the tenured employee should be put under another supervisor. It should be remembered that the cost of training a new employee is astronomical compared to the cost of retaining a tenured employee .    

Its time for his to be pushed up the ladder then if his credibility and abilities are proven and he has turned into an asset from an employee

Jealous subordinates will make a team leaders job impossible. The best way to deal with it is to assign tasks for the jealous ones away from the productive ones. This way you're still a team but not so close where anything can go wrong.

Jealous is normal feelings to each person. Avoid jealous ,to treat people in the company staff ,head or not as long this person is belong, you must treat people in fair.