Two crucial issues must first be addressed.

1. Are the astrological houses valid?, and...
2. Just where does the Midheaven fit in?

Long time readers of this site know that the houses are little more than the relationship of the planets(by sign) to the Earth/Ascendant. Mars in the fifth house, for example, is really Mars in lower or dexter trine(by sign) to the Earth/Ascendant. The houses are therefore inventions which hide the true nature or role of our planet in astrology. Also, there is too much silly emphasizing of degrees in astrology, and this has caused us to go astray on the basic issues. Remove houses and degrees from astrology and everything clears up or falls into place. What we have left are the planets, signs, and seven basic aspects, five of which double up. The Ascendant or Rising is none other than the influence of our own planet Earth and the Midheaven or celestial sphere is simply the projection of our hollow planet's inner central sun(also a planet in it's own right).

We now have twelve planets to work with, each of which can become a career significator. What determines whether a planet is a career significator or not?

Career, profession, or status, is the domain of Capricorn, the tenth sign of the zodiac, and Saturn its ruling planet. Capricorn or Saturn is also the upper square aspect(by sign) in astrology or what we would call the tenth house(both the same thing).

Therefore the principle indicators or career significators in a chart are...
1. the Saturn sign
2. any planet in Capricorn
3. any planet in upper square(or tenth-house relation) to any other planet

This can mean that ALL of your planets are career significators in some way, especially if you have a planet in every sign. This should not seem so unusual, as it is not uncommon for some people to be totally geared to their profession, while others only partially so.

Begin by assessing your Saturn placement. Saturn shows how or where you can plan, organize, and achieve an objective.
Saturn in fire has personal goals or objectives, such as achieving a clearer sense of self or identity(Aries), personal fame or power(Leo), or spiritual illumination(Sagittarius).
Saturn in earth has material goals or objectives, such as achieving wealth and possessions(Taurus), health and skill(Virgo), or some position of power and authority(Capricorn).
Saturn in air has social or intellectual goals or objectives, such as achieving knowledge or learnedness(Gemini), unity or harmony(Libra), and freedom or truth(Aquarius).
Saturn in water has security goals or objectives, such as achieving a sense of belonging or family(Cancer), fusion or regeneration(Scorpio), or universal compassion or understanding(Pisces).

Planets in Capricorn show ambition, industriousness, professionalism, and a sense of space, sequence, order, timing, definition, or organization -traits which will play important roles in any career.
Sun, Mars, or Jupiter in Capricorn: produces individuals whose main objective in life is to achieve some kind of name, status, or position of power or authority for themselves. They are serious, organized. and industrious and are often the powers behind companies, buisnesses, or government institutions.
Mercury, Ascendant, or Uranus in Capricorn: produce individuals similar to the first group, although on a more social or intellectual level. These people enjoy organizing, assessing, defining, and are also often employed in some buisness, managerial, or government capacity.
Moon, Neptune, and Pluto in Capricorn: produces individuals who use their keen or intuitive buisness sense for profit or gain. They are often involved in the more hidden or secretive roles of buisness, industry, or government, particularly in the case of the two outermost planets.
Midheaven, Venus, and Saturn in Capricorn: produce individuals with solid or practical buisness and organizational skills, and who can easily achieve positions of power, status, or authority.

Planets in upper or tenth-house square by sign(the closeness by degree intensifies it all) also achieve career prominence in some way. If you are a Leo Sun sign, for example, any planet in Taurus will become a career significator in some way. The nature of the planet will specify this. If it is Mars in Taurus, for example, the career may involve atheletism or the military. If it is Jupiter -travel or the ministry, and so on. The sign involved will of course give further clues.

This can be done not only with the Sun sign or Ascendant but with the Midheaven or any other planet in the chart. Take each of your planets, one by one, and see how many produce a tenth house planet. The lower square planet(placed in the Ascendant position) and its nature must also be considered, as it is what fuels or supports the upper square or tenth house planet.

It can also work the other way around with the tenth house planet casting the lower square planet into prominence. In this situation the tenth house planet becomes the "power behind the throne". A Leo planet, for example, will not fully flower or develop unless goaded or "bossed" by a Taurus planet. Taurus is the natural tenth-house boss or authority figure for Leo.

In this sense, any planet in square by sign, and especially if it is a tight or close square by degree, is a potential career significator. Other aspects to such a planet can of course play supporting or detracting roles.

One can even go a step further and single out any planetary placement as a career significator by virtue of its root configuration. Sun in Taurus, for example, is a placement where both the planet and the sign are in square or in a fourth-tenth house relation to one another. So is Venus in Leo, Mars in Cancer, Jupiter in Virgo, or any other square configuration between planet and sign. This, however, requires an established knowledge of sign rulership which is presently incomplete.