Having recently read a biography of this great man, I was not satisfied that the "noon" figure with Taurus rising was correct. Instead I have come up with a time of 2.04 pm with an Ascendant of 18.50 Gemini:
Transits to the angles or Lot of Fortune for significant events (not all found are shown):
Ordained to the Baptist ministry, February 25, 1948 - t Saturn 17.59 Leo sextile Asc.
Received Doctorate of Philosophy in Systematic Theology from Boston University, Boston, Massachusetts on June 5, 1955 - t Saturn 15.57 Scorpio square Lot of Fortune.
Yoland Denise, King?s first child, is born at Montgomery, Alabama on November 17, 1955.
November 25: The Interstate Commerce Commission banned segregation in buses and all waiting rooms involved in interstate travel
December 1: Rosa Parks, a 42 year old seamstress, is arrested in Montgomery, Alabama for refusing to give her seat on the bus to a white male passenger.
December 5: Martin Luther King becomes the president of the Montgomery Improvement Association which was organised due to protest against the incident involving Rosa Parks and the Montgomery bus boycott begins. Range of t South Node from November 17th to December 5th is 18.29 to 17.32 Gemini conjunct Asc.
Supreme Court rules that bus segregation is illegal, ensuring victory for the bus boycott, November 13, 1956 - t North Node 29.04 Scorpio square MC.
Congress of the United States passes the Civil Rights Act of 1957, September 9th - t North Node 13.25 Scorpio square Fortune.
Dr. King is stabbed by a woman while at a book signing in a department store in Harlem, New York. September 20, 1958 - t Saturn 19.42 Sagittarius opposite Asc, T Mars 29.50 Taurus square MC, T Uranus 14.39 Leo conjunct Fortune.
Martin Luther King meets with President John F. Kennedy and after their meeting Dr. King delivers his famous "I Have a Dream" speech on the steps of the Lincoln Memorial to a crowd estimated at 250,000 at the Marche on Washington for Jobs and Freedom. August 28, 1963 - t Saturn 18.38 Aquarius trine Asc, t Jupiter 18.54 Aries sextile Asc.
Martin Luther King becomes the youngest person to receive the Nobel Peace Prize in Oslo, Norway for his efforts to end segregation and racial discrimination through non-violent means. December 10, 1964 - t Saturn 29.36 Aquarius conjunct MC.
March 28, 1968 ? King leads striking sanitation workers in a march in Memphis, Tennessee. The march erupts in violence.
April 3 ? Dr. King delivers his last speech at a rally at Mason Temple (the national headquarters of the Church of God in Christ), Memphis. The famous and inspiring ?I?ve Been to the Mountaintop speech ?
April 4: While standing on the balcony of his room at the Lorraine Motel in Memphis, Tennessee Dr. Martin Luther King is shot and killed.
t Saturn 14.21 - 15.18 Aries trine Fortune, t North Node 18.59 Aries on April 4th sextile Asc.

Posthumous - National holiday granted in his honor, November 2, 1986 - t North Node 19.38 Aries sextile Asc, t Mercury station 29.09 Scorpio square MC.

Synastry with his assassain James Earl Ray (http://www.astro.com/astro-databank/Ray,_James_Earl):
Ray's Saturn: 18.51 Sagittarius opposite King's Asc (orb 0.01).
Ray's Moon: 9.09 Scorpio conjunct King's Vertex (10.19 Scorpio).
Ray's Sun (in his 8th house): 20.03 Pisces conjunct King's Moon (20.42 Pisces).

Summary Statement of MLK's life: MLK is a man of God who leads a non violent revolutionary movement of (descendents of) slaves seeking equal rights. He mobilises the movement with his exceptonal oratory. The struggle is long and difficult, and is violently opposed and repressed by the government/government supporters. It is ultimately successful. MLK has a weakness for women and has secret affairs which are used against him (unsuccessfully) by the government (read: FBI director J. Edgar Hoover). Leading the movement takes a toll on MLK's health (autopsy showed him to have the heart of a 60 year old although he was only 39). MLK is publicly assassinated by a sniper.

Let's break this down with the astrology:

MLK is a man of God who leads a non violent revolutionary movement of (descendents of) slaves seeking equal rights. He mobilises the movement with his exceptonal oratory.

Gemini rises and Mercury is in the 9th, the house of God in the humanitarian sign Aquarius. Mars is in Gemini - Mars rules the 6th (slaves) and the 11th/Spirit (mass movements, political or otherwise - King is effective at leading such a movement because spirit ruler is in the rising sign). The movement is of a revolutionary nature because Uranus is in Aries/11th with spirit - but why non-violent? The outlet for Mars/Gemini/retrograde is not violence, but oratory signified by reception with Mercury/Aquarius. The strong Pisces inflence of the 10th of Praxis (action) where Moon (tightly applying to Mars) and Venus reside also makes the native inclined towards peace.

The struggle is long and difficult, and is violently opposed and repressed by the government/government supporters. It is ultimately successful.
The struggle is signified by the Mars - Saturn opposition straddling MLK's Asc-Desc axis. Saturn rules the 8th (death), 9th and MC (government). Saturn/Sagittarius signifies the government using legal means (read: laws) to oppress slaves. MLK and the movement he leads, signified by Mars, rails against this. Why was the movement successful? Strong 11th house ("Good spirit") influence - Mars rules the 11th (and 6th) and is in the 11th sign from Fortune - a very powerful and effective place for any planet to be in. In addition, the ultimate outcome of government legal oppression (Saturn/Sagittarius) is signified by ruler Jupiter in Taurus/12 - in mutual reception with Venus/Pisces/10th - MLK's peace movement "won" by getting congress and LBJ to pass the civil rights act.

MLK has a weakness for women and has secret affairs which are used against him (unsuccessfully) by the government (read: FBI director J. Edgar Hoover).
This is signified by the Venus-Jupiter mutual reception in the 10th-12th respectively, Jupiter rules Saturn/Sag/7th. The affairs were kept hidden from the public during his lifetime, showing 12th house influence.

Leading the movement takes a toll on MLK's health (autopsy showed him to have the heart of a 60 year old although he was only 39). MLK is publicly assassinated by a sniper.

The Lot of Fortune is the lot of the Moon and consequently has significations to do with the physical body - MLK's is in Leo, sign of the heart adding emphasis to the Sun's general significations of the heart. It is in Capricorn/8th of death in MLK's chart - this signifies premature ageing of the heart because of the stress from the struggle (signified by ruler Saturn opposite Mars). But king didn't die of a heart attack, he was shot. The malefics in opposition across the 1st - 7th, Moon's position in 8th from Fortune (deadly place) applying to Mars, ruler of Basis in 8th from fortune, ruler of Fortune in 8th from Asc are all indicators of short life and potential for a violent death.